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Two novel nonlinear optical (NLO) chromophores JC-T-TCF and JC-F-TCF utilizing tetramethyljulolidine-based coumarin and tricyanofuran(TCF) as the electron donor and acceptor, respectively, were designed and synthesized. The two chromophores were linked with different π conjugated electron bridge (thiophene group and furan group), which provide the opportunity to study the structure–property relationship of coumarin-based chromophores. Both the novel obtained chromophores exhibited reasonable stability and solvatochromic effect. The theoretical calculation results indicated that both chromophores possess microscopic hyperpolarizability (β) in excess of 320 × 10−30esu, and the chromophore JC-T-TCF utilizing thiophene group as the electron bridge exhibited obviously larger β value (456.8 × 10−30esu). The larger β value, combination with the larger µ value, endowed JC-T-TCF with larger electro-optic activity of 70 pm V−1 at the wavelength of 1310 nm in the guest–host films of chromophores doped into PMMA, which provide the potential application opportunity in the field of optical waveguide devices. [ABSTRACT FROM AUTHOR]

Developing new organic chromophores with a large electro-optic coefficient (r33) is highly desirable for fabricating electro-optic (EO) materials. Building on the fact that the 1,1,7,7-tetramethyl julolidine fused furan ring is a good electron donor and lengthening the π-bridge of a chromophore with a five-membered heterocycle ring could lead to the improvement of r33. Here we design and synthesize two new chromophores C1 and C2 by using a 1,1,7,7-tetramethyl julolidine fused furan ring as the electron donor and 2-(3-cyano-4,5,5-trimethyl-5H-furan-2-ylidene)-malonitrile (TCF) as the acceptor, but with two different π-bridges (furan-vinylene and thiophene-vinylene accordingly). When doping C1 or C2 into PMMA with a loading density of 20 wt%, the poled films containing C1 or C2 exhibited an r33 value of 75 pm V−1 and 94 pm V−1, respectively. When compared with chromophore C3 (an ene unit as the π-bridge, r33 = 52 pm V−1), an enhanced r33 of C1 and C2 was achieved due to the introduction of a heterocycle ring into the π-bridge. This work uncovers the influence of the heterocycle ring on the julolidine fused furan based chromophore's physical and chemical properties and demonstrates that the new chromophores are a promising candidate for EO material application. [ABSTRACT FROM AUTHOR]

Buchwald-Hartwig amination of aryl halides with solvent-free condition was used for the preparation of electron donors with high density of electron cloud. Organic second order nonlinear optical chromophore ZML-c based on this electron donor was designed and synthesized. And chromophore ZML-ref without modified groups was also prepared as the contrast. Their delocalized energy levels were estimated by UV–Vis. spectra. Their thermal properties were studied by thermogravimetric analysis (TGA). Obviously, chromophore ZML-c showed lower delocalized energy levels and lower thermal decomposition temperature (just about 160 °C). The poled films showed the largest electro-optic (EO) coefficients of 23.5 pm/V and 10.6 pm/V respectively for chromophore ZML-c and ZML-ref. These results indicate that effective modification in indole ring may be a promising way to drastically change the electro-optical features of the titled compounds and show a direction of designing new electron donor in the field of nonlinear optical materials. [ABSTRACT FROM AUTHOR]

Organic nonlinear optical materials have been widely explored because of their advantages in the design of materials with large electro-optic coefficients used in the fabrication of novel optoelectronic and telecommunication devices. However, the huge dipole-dipole interactions between organic nonlinear optical chromophores have limited further improvements in the electro-optic coefficients and long-term material stability. Here, a novel polymer based on poly(aryl ether ketone) was designed and prepared to enhance the electro-optic coefficients and achieve higher long-term stability. This novel poly(aryl ether ketone) has a relatively high glass transition temperature and offers active functional groups for the attachment of organic nonlinear optical chromophores. After attachment of nonlinear optical chromophores the materials showed higher chromophore loading density, less inter-molecular interaction, and suitable solubility. This resulted in better film-forming ability, higher electro-optics coefficients and better long-term stability. Quantum chemical simulations of the second order hyperpolarizabilities and ground sate dipole moments were done to understand the origin of the effects. [ABSTRACT FROM AUTHOR]

Highly efficient and thermally stable nonlinear optical chromophores based on the same thiophene π-conjugation and tricyanofuran acceptor (TCF) possessing different isolation groups attached to electron-donating moiety have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These new chromophores showed excellent thermal stability with their decomposition temperatures all above 250 °C. Most importantly, the molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r 33 ) in poled polymers. The doped films-B containing 25 wt % chromophore F1 displayed an r 33 value of 52 pm/V at 1310 nm, and the doped films-C containing F2 showed a value of 91 pm/V at the concentration of 35 wt %. These values are all much higher than the traditional FTC chromophore (39 pm/V). These results revealed that the introduced isolation group can reduce intermolecular electrostatic interactions thus enhance the macroscopic EO activity. Besides, the position of the isolation group plays an equally important role in achieving the ultra large EO coefficients of materials. These properties, together with the good solubility, suggest the potential use of these new chromophores as advanced materials devices. [ABSTRACT FROM AUTHOR]

Due to the simple preparation technology and appropriate crosslinking process, polyurethane was selected as the host polymer for the preparation of organic electro-optics (EO) materials. The synthesis and crosslinking process of polyurethane demanded the nonlinear optical (NLO) chromophore possessing strong stability in acid environment. Fortunately, after the introduction of azo group in the electronic bridge, the stability of this kind of chromophores in acidic environment was improved greatly. Polyurethane EO polymers and EO films based on this kind of chromophore were prepared successfully. The crosslinking process was monitored by infrared spectroscopy clearly. The crosslinking process has direct relationship with the molecular weight of the crosslinkers. Crosslinker of triethanolamine with small molecular weight showed low crosslinking temperature (80 °C) and short crosslinking time (20 min). The crosslinking temperature and time was improved to 140 °C and 60 min based on Poly(bisphenol A glycidyl ether aniline) (BPAN) crosslinker with large molecular weight. More importantly, this kind of EO polymers showed us large second order nonlinear optical coefficients (76.1 pm/V) and good long term stability (130 °C). [ABSTRACT FROM AUTHOR]

Organic electro-optic (EO) materials have been widely explored and used in the fabrication of microwave photonic devices. Their principal advantages are the follows: lower half-wave voltage, wider bandwidth, lower cost and more convenience of integration. Organic second order nonlinear optical (NLO) chromophores, as the core of the organic EO devices, define the key technological parameters: EO efficiency, long term stability, solubility and optical losses. In the present review article, the use of D–π–A chromophore molecules with polycyclic electron donors based on julolidinyl structure is reported and discussed. Significant improvement of electron donating ability and appropriate isolated effect are shown. Future perspectives of the application of such kind of NLO chromophores are considered. [ABSTRACT FROM AUTHOR]

Polymers based on N-phenyl maleimide, N-4-propargyl methoxy phenyl maleimide and methyl methacrylate was synthesized. High glass temperatures 183, 179, 159 °C respectively for P 1 , P 2 and P 3 were achieved. EO polymer P 3 –C 1 , P 3 –C 2 and P 3 –C 3 with about 30 wt% chromophore loading density were prepared by attaching Chromophore C 1 , C 2 and C 3 to polymer P 3 using copper-catalyzed Huisgen cycloaddition reactions in mild reaction conditions and high yield. Among the EO polymers, P 3 –C 3 showed us the best solubility in normal solvents and suitable glass temperature. EO films based on EO polymer P 3 –C 3 showed us large EO coefficient of 50 pm/V @1310 nm and good long-term stability, 85% EO activity was kept after annealing at 85 °C for 200 h. [ABSTRACT FROM AUTHOR]

Two principally novel organic nonlinear optical chromophores (1 and 2) with flexible ( n-hexyl group) or rigid isolated (benzyl group) group are designed and successfully synthesized. The prepared chromophores were characterized by MS, H-NMR and UV-Vis spectra. Their thermal stability was studied by thermal gravimetric analyzer and differential scanning calorimetry. Poled films of the chromophores doped in amorphous polycarbonate afford the maximum electro-optic tensor coefficient (r) equal to 39 pm/V, 63 pm/V for chromophore 1 and chromophore 2, respectively at the wavelength 1,064 nm. The reason of so large differences between these two chromophores' linear electrooptics coefficients were explained within a framework of performed quantum chemical calculations and it is crucially dependent on distances between the chromophore molecules and the polymer chains. [ABSTRACT FROM AUTHOR]

A new series of Y-type polyurethanes containing different concentrations of nonlinear optical (NLO) chromophore with aniline donor and tricyanofurane (TCF) acceptor have been successfully prepared, and characterized by FTIR, UV-Vis, and 1H-NMR spectra. New polyurethanes were synthesized with different chromophore contents by introducing diol N, N-dihydroxyethylaniline or 4-[ N, N-(dihydroxyethyl)amino]benzaldehyde. These NLO polyurethanes exhibit good film forming property and high thermal stability up to 281°C. The highest electro-optic coefficient ( r33) of polymers is up to 39 pm V−1 measured by simple reflection technique at 1310 nm, and the temporal stability of the poling-induced order at elevated temperature of 80°C was much improved through the introducing of hydrogen bonding interaction in this system. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Three chromophores with tricyanofuran and tricyanopyrroline electron acceptors were synthesized and doped in high glass transition temperature ( T) polymer poly( N-(4-acetoxylphenyl)maleimide-co-styrene, NAPMI-co-ST). The electro-optic (EO), optical, and thermal properties of the doped poly(NAPMI-co-ST) were characterized and discussed. After being corona poled under 12 kV, this high T polymer material showed excellent EO activity and thermal stability. The highest EO coefficient ( r) reached 48.2 pm V (1,310 nm) and could remain 90 % of the original value for 100 h at 85 °C. The EO coefficient was relatively higher compared with other high T EO polymers. The thermal stability was also very good and the manufacture process was convenient and applicable for device fabrication. [ABSTRACT FROM AUTHOR]

Two novel soluble polyarylates with different nonlinear optical chromophores as the side chains were prepared and characterized by UV-visible spectra, nuclear magnetic resonance, and infrared spectroscopy. The titled polymers show us good thermal stability; the thermal decomposition temperature values were 201 and 253 °C, respectively, for polymer sPAR-CTCF and sPAR-CTCP. The glass transition temperatures were 139 and 122 °C for sPAR-CTCF and sPAR-CTCP, respectively. Chromophore FTC-wl was doped in these polymers as a guest chromophore to form binary chromophore electro-optic (EO) system. And super large EO coefficients (124 pm/V) were found from FTC-wl-doped sPAR-CTCP binary chromophore system at high chromophore loading density. [ABSTRACT FROM AUTHOR]

Abstract: A novel chromophore BDT–TCF with benzo[1,2-b:4,5-b′]dithiophene (BDT) unit as electron bridge was synthesized and characterized by UV–vis, NMR spectroscopy, and thermal analysis. It is the first time that BDT unit was introduced into NLO materials. The chromophore showed excellent solubility in most common solvents, and good thermal stability for practical applications. The second order nonlinear optical effect was measured by hyper Rayleigh scattering method. The diagonal hyperpolarizability β zzz of BDT–TCF was 8.2×10−28 and 9.3×10−29 esu in THF solvent and in PMMA polymer matrices, respectively. The potential NLO response indicates that BDT unit is a promising π-electron bridge and an excellent candidate for nonlinear optical devices. [Copyright &y& Elsevier]

A tricyanopyrroline chromophore with methacrylate reactive group was synthesized to fabricate the side chain (polymer 1) and crosslinkable (polymer 2) EO (electro optic) polymers with enhanced electrooptical tensor coefficients. These type of polymers have demonstrated the large EO coefficients with values of 29 pm/V and 25 pm/V at wavelength 1,310 nm, respectively. Compared with polymer 1, t polymer 2 had demonstrated a better stability of polar structure. The thermal stability of polar structure was improved for about 100 °C. The temperatures of poling and crosslinking processes were compatible in polymer 2, which allowed obtaining the EO films with improved features. The experimental results have been interpreted with the aid of quantum-chemical calculations. [ABSTRACT FROM AUTHOR]

A new nonlinear optical chromophore with strong electron-withdrawing acceptor and rigid-flexible dendron was synthesized. An electro-optic (EO) attenuated total reflectance modulator was prepared to measure the EO coefficient of the films. Modification of the tricyanopyrroline chromophore with rigid-flexible dendron group provided reduction of dipole-dipole interactions and improvement of its solubility. As the chromophore loading increased, there was a great improvement on the macroscopic EO response of the polymeric materials obtained by incorporating this chromophore as a guest in amorphous polycarbonate. The largest EO coefficient was 42 pm/V at 1310 nm. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Organic electro-optic (EO) materials have been widely studied and used in microwave photonic devices, due to their advantages in half-wave voltage, bandwidth, low cost and ease of integration. Nonlinear optical (NLO) chromophores, as the core of organic EO materials, can directly decide the characters of organic EO materials, including large EO activity, long term stability, solubility and optical loss. Auxiliary donors have attracted great attentions in NLO chromophores for their strong electron donating ability and significant isolation effect. This feature article describes the application of auxiliary donor in NLO chromophores, including the EO activities, optical characters, stability, crystal structures and machinability. [ABSTRACT FROM AUTHOR]

Dual D-Pi-A nunchaku-like structure chromophore was designed and synthesized to improve electro-optic (EO) materials׳ EO coefficients ( r 33 ) and long term stability by a simple doping system. The r 33 values of poled APC/10% DIMER1 and APC/20% DIMER1 are 23 pm/V and 45 pm/V respectively. After annealed at 85 °C for 500 h, the poled film of APC/20% DIMER1 can retain more than 85% of its initial r 33 value. All these characters showed us superior prospects of application in EO devices. Chromophore DIMER1 also showed us good thermal stability; its decomposition temperature (Td) was higher than 280 °C, which is enough for its application in the EO devices. Also chromophore DIMER1 had good solubility in amorphous polycarbonate (APC); it could be dissolved in APC at high loading density (25%). [ABSTRACT FROM AUTHOR]

Novel nonlinear optical (NLO) chromophore based on 6-(pyrrolidin-1-yl)-1H-indole as the electron donor group was designed and synthesized. The molecular structure of this chromophore was characterized by 1 H NMR spectra, 13 C NMR spectra, and MS spectra. The delocalized energy level was estimated by UV–Vis. spectra. The thermal property was studied by thermogravimetric analysis (TGA). The poled films containing chromophores ZML-1 with a loading density of 10 wt% in amorphous polycarbonate (APC) afford an average electro-optic (EO) coefficient ( r 33 ) of 19 pm/V at 1310 nm. Compared to the reported aniline-based chromophore ( r 33 = 12 pm/V) analogues, chromophore ZML-1 exhibits enhanced electro-optical activity. [ABSTRACT FROM AUTHOR]

Benchmark chromophore C1 and counterpart chromophore C2 with the same electron donor and acceptor was designed and synthesized to compare their different electro-optic coefficients and long term stability by doping system. The electro-optic coefficient of a poled film containing 25 wt% of C1 doped in amorphous polycarbonate (25 wt% C1 /APC) afforded a value of 22 pm/V at 1310 nm, while 25 wt% C2 /APC afforded a value of 60 pm/V. After annealing at 85 °C for 500 h, the poled film of 25 wt% C2 /APC could retain more than 85% of its initial r 33 value. In contrast, only 75% of the initial r 33 value of the poled film of 25 wt% C1 /APC was kept after 300 h. The excellent thermostability and its good temporal stability in APC made C2 a favorable candidate for practical application. [ABSTRACT FROM AUTHOR]

Abstract: A novel nunchaku-like organic second order nonlinear optical chromophore containing a D–π–A backbone and a rigid biphenylene unit was prepared. The UV–vis absorption spectra studies demonstrated that the large rigid structure could suppress dipole–dipole interactions effectively. The electro-optic coefficient of a poled film containing 20% wt of the new dye doped in amorphous polycarbonate afforded a value of 39 pm/V at 1310 nm. Compared with results obtained from a similar D–π–A chromophore without the rigid isolated group, the new dye gave better performance. Moreover, the electro-optic film prepared with the new dye gave greater temporal stability, compared to a similar D–π–A doped poled film that was reported previously. These results indicated that the introduction of a biphenylene group could effectively reduce the intermolecular electrostatic interactions and aid the alignment of the chromophores. [Copyright &y& Elsevier]

Highlights • A new chromophore was investigated. • Phenothiazine with rich electron sulfur and nitrogen heteroatoms was introduced. • The new structure chromophore showed good nonlinear optical properties. Abstract A novel chromophore based on the phenoxazine and tricyanofuran acceptor linked together via thiophene as the bridges have been synthesized by the conventional technique and systematically investigated. Structure analysis and photophysical properties were carried out to investigate the new structure chromophore. Density functional theory was used to calculate the hyperpolarizability (β) and the result shows that chromophore A showed a lower energy gap. In addition, chromophore A displayed good thermal stability with the onset decomposition temperature over 240 °C. These results showed that chromophore A, which had good thermal stability and nonlinear optical properties was a promising candidate for practical use. [ABSTRACT FROM AUTHOR]

Abstract Novel nonlinear optical chromophores JC-TCF and JC-FTCF using tetramethyljulolidine-based coumarin as the electron-donor and tricyanofuran derivatives as the electron acceptors were designed, synthesized and investigated. The obtained chromophores own good solubility in common solvents, and good compatibility with host polymers. The chromophores also have good thermal stability, and the decomposition temperature exceed 200 °C. The UV–vis spectra indicated that JC-TCF and JC-FTCF possess good intramolecular charge transfer ability. Density functional theory (DFT) was used to study the energy gap and first-order hyperpolarizability(β). After contact poling, the guest-host polymer films of polymethyl methacrylate containing 20% wt JC-TCF and 20% wt JC-FTCF exhibited the highest electro-optic coefficient (r 33) up to 40 p.m./V and 76 p.m./V respectively, and the results indicated the chromophores' microscopic β value could be effectively translated to macroscopic EO activity, and the tetramethyljulolidine-based coumarin could be an useful candidate in the development of NLO materials. Highlights • Julolidine-based coumarin was used as electron-donor in design of NLO materials. • The coumarin's good electron-donation ability obviously enhanced the NLO properties. • The obtained materials exhibited better EO activity compared to the FTC chromophores. • The maximum EO activity of reported NLO chromophores reached to 76 p.m./V. • Coumarin could be an useful candidate in the development of NLO materials. [ABSTRACT FROM AUTHOR]

One novel chromophore C based on 4,4′-bis(diethylamino) benzophenone donor and CF 3 -Ph-TCF acceptor was synthesized. Alkoxy isolation group was introduced also. Cyclic voltammetry measurements showed that the new chromophore C had a much smaller energy gap (ΔE = 1.25 eV) than chromophore A and B. UV–Vis absorption indicated that obvious red shift (more than 100 nm) obtained for chromophore C. The doped film C containing CF 3 -Ph-TCF chromophore showed a r 33 value of 235 pm/V at the concentration of 25 wt% which is much higher than that of the TCF based chromophore A (149 pm/V) and B (163 pm/V). The thermal stability were high enough (>200 °C) to be further fabricated in devices and good EO property make application possible. [ABSTRACT FROM AUTHOR]

Two novel bichromophores YL1 and YL2 based on traditional aniline chromophore YL were synthesized by Cu(I) catalyzed click-reaction and systematically investigated in this paper. The UV–Vis, electrochemical property, thermal stability and EO activity of these chromophores were systematically studied and discussed. These two bichromophores showed good thermal stability. Then nonlinear optical polymer films were fabricated by doping chromophores into polymethylmethacrylate (PMMA). The doped films containing bichromophores YL1 and YL2 showed r 33 values of 20 and 17 p.m./V at concentration of 25 wt% at 1310 nm. These values were respectively 2.85 times and 2.43 times of the EO activity of chromophore YL (7 p.m./V). High r 33 values indicated that the new structure of bichromophores YL1 and YL2 can reduce intermolecular electrostatic interactions, thus enhancing macroscopic EO activity. These properties suggested the potential use of the new bichromophores in nonlinear optical materials. [ABSTRACT FROM AUTHOR]

A novel chromophore based on N -(4-dibutylaminophenyl)tetrahydroquinolinyl donor group was synthesized to compare with traditional chromophores based on either diethylaminophenyl or triarylaminophenyl donor groups. Cyclic voltammetry measurements showed that the new chromophore had a much smaller energy gap than the structurally related chromophores. Density functional theory calculations suggested that the molecular quadratic hyperpolarizability (μβ) value of tetrahydroquinolinyl chromophore is 65% and 110% larger than that of either the diethylaminophenyl or triarylaminophenyl chromophores, respectively. The doped film containing the tetrahydroquinolinyl chromophore showed an r 33 value of 126 pm/V at the concentration of 25 wt% which is much higher than the electro-optic activity of the diethylaminophenyl derived chromophore (39 pm/V) and six times higher than that of the traditional triarylaminophenyl chromophore (19 pm/V). The tetrahydroquinolinyl chromophore possesses much higher thermal stability (with its onset decomposition temperature above 280 °C) than those of commonly used alkyl chromophores. [ABSTRACT FROM AUTHOR]

Fluorine was non-conjugatedly linked to the donor of nonlinear optical chromophore to investigate the effect of highly electronegative fluorine on intramolecular charge-transfer and electro-optic activities. 1 HNMR spectra and UV–vis absorption were used to investigate that introduction of fluorine change the dielectric environment of intramolecular charge-transfer. Fluorinated chromophore showed more intensified absorption and its absorption properties was more stable to dielectric change in solution. In solid state of guest-host electro-optic polymer films, this dielectric environment stabilization was revealed to attenuate the dipole–dipole interactions of chromophores. Higher electro-optic coefficients (148 pm/V) and higher chromophore loading density (30 wt%) of fluorinated material chr-2/APC than benchmark material chr-1/APC (116 pm/V at 25 wt%) was achieved. [ABSTRACT FROM AUTHOR]

Three novel nonlinear optical chromophores based on the same bis( N,N -diethyl)aniline donor have been synthesized and systematically characterized. These chromophores showed good thermal stability and chromophore y1 showed the best thermal stability of 249 °C. Besides, compared with the chromophore (y1) without the substituted group, chromophores y2 and y3 show better intramolecular charge-transfer absorption. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic coefficients. The electro-optic coefficient of poled films containing 25% wt of chromophores y1–y3 doped in amorphous polycarbonate afforded values of 149, 138 and 157 pm/V at 1310 nm for chromophores y1–y3 respectively. These results indicated that the double donors of bis( N,N -diethyl)aniline unit can efficiently improve the electron-donating ability and the special structure can reduce intermolecular electrostatic interactions, thus enhancing the macroscopic electro-optic activity. These properties, together with good solubility, suggest the potential use of these chromophores as advanced materials. [ABSTRACT FROM AUTHOR]

Two novel chromophores based on the phenoxazine (chromophore L1) or phenothiazine (chromophore L2) donor, and tricyanofuran acceptors linked together via thiophene as the bridges have been synthesized and systematically investigated. Cyclic voltammetry measurements showed that chromophore L1 had smaller energy gap than chromophore L2 due to the stronger electron-donating ability. Moreover, Density functional theory calculations suggested that the β value of chromophore L1 is 17% larger than that of chromophore L2. The doped film containing the chromophore L1 showed an r 33 value of 49 pm/V at the concentration of 25 wt% which is two times higher than the EO activity of the chromophore L2 (23 pm/V) and the traditional aryl chromophore (10–20 pm/V). High r 33 value, high thermal stability (onset decomposition temperatures higher than 220 °C) suggests the potential use of the new chromophore in nonlinear optical materials. [ABSTRACT FROM AUTHOR]

A novel nonlinear optical chromophore with rigid 3-bromo-thiophene (denoted as BTC) as a site-isolation group to suppress the dipole-dipole interaction, was designed and synthesized. UV–vis absorption indicated that BTC showed intensified absorption and large bathochromic solvatochromism. The electro-optic performance studies displayed a highest r 33 value (93 pm/V) at high chromophore loading density of 45%, which indicated that the dipole-dipole interactions were effectively suppressed. The Crystal analysis further demonstrated that the face-to-face antiparallel packing with a long distance of 7.388 Ǻ between the neighboring chromophores was observed. This weak packing interactions suggested that BTC chromophores can be well isolated in electro-optic materials for chromophores’ high efficient alignment. The excellent electro-optic performances endowed BTC potential application in the high-performance electro-optic materials. [ABSTRACT FROM AUTHOR]

Abstract: A series of novel second-order nonlinear optical chromophores containing additional heteroatoms in donor moieties has been synthesized and systematically characterized. The resulting nonlinear optical chromophores exhibited both good thermal stability (the decomposition temperature in the range of 249 °C–275 °C) and good solubility in common organic solvents such as chloroform, acetone and N, N-dimethyl formamide. In order to investigate the influence of additional heteroatom on the electro-optic activities, UV–Vis spectra and density functional theory calculations were carried out. The results revealed that the donor derived from m-phenylenediamine had higher electron density compared with other three donors. As to electro-optic activities, the doped polymer film-C displayed the highest electro-optic coefficient value of 31 pm/v at the doping concentration of 20 wt%. All these results indicated that the nonlinear optical activities could be enhanced by introducing suitable additional heteroatoms into donor moiety. [Copyright &y& Elsevier]