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Phosphate glasses of calcium oxide have been well proved materials for various bio bones and dental implants. However, still there is a lot of scope and demand to produce efficient elastic bio implants and resource. In view of this, Zr x Ca 30-x P 70 phosphate materials are prepared by using melt quenching method. Bio, physical, thermoluminescence and elastic techniques are used to characterize the samples. Additionally, simulated body fluid was prepared and it is used especially for bio techniques. Further, the glasses are taken for different dose (~0, 10, 20 & 50 kGy) of gamma irradiation around half an hour. And again similar techniques are used to characterize the samples. All the findings from bio, physical, thermoluminescence and elastic characterization results are analysed and took for better comparison with previous studies to develop various bio bone (or) bio dental resource. Structural reports suggests that the Zr x Ca 30-x P 70 materials were glassy before immersion in SBF solution and immersed (~720 h) samples are showing partial ceramic nature. The weight loss and pH reports suggests them for alternative bio resource as a bio bones and dental implants. Observed thermal stability, microhardness and elastic modulus evaluations of Zr x Ca 30-x P 70 materials in required standards are also additional advantage. Furthermore, thermoluminiscence (TL) under different γ-irradiation doses is reported for glasses with and without immersing in a simulated body fluid. The glasses lose TL intensity when immersed in simulated body fluid for nearly 720 h. This is useful to modulate bio-behaviour in terms of hydroxyapatite layer growth on the glass surface., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The glasses of the composition 19Na(2)SO(4)-20MO-60P(2)O(5): 1.0Ho(2)O(3)/1.0Er(2)O(3) (M=Mg, Ca, and Ba) have been synthesized. Optical absorption and fluorescence spectra (in the spectral range 350-2100 nm were studied at ambient temperature. The spectra were characterized using Judd-Ofelt theory. From the luminescence spectra, various radiative properties like transition probability A, branching ratio β and the radiative life time τ for blue (B), green (G) and red (R) emission levels of these glasses have been evaluated. The energy transfer between the two rare earth ions (Ho(3+) and Er(3+)) in co-doped Na(2)SO(4)-MO-P(2)O(5) glass systems in the visible and NIR regions has also been investigated. Highest intensity, the highest quantum efficiency and maximum energy transfer with low phonon losses of B, G, and R lines has been observed in BaO mixed glasses. The reasons for such higher values of these parameters have been discussed in the light of varying field strengths at the rare earths ion site due to replacement of one modifier oxide with the other. The enhanced intensity of NIR emission (at 2.0 μm) has also been discussed in terms of cross relaxation of Er(3+) ions from (4)I(13/2) level to (5)I(7) of Ho(3+) ions., (Copyright © 2011 Elsevier B.V. All rights reserved.)

This investigation consists of results of the studies on dielectric properties and a.c. conductivity of Li2O-Ga2O3-SiO2 (LGS) glass with 2.0 mol% of Cr2O3, MoO3, WO3 across 0.01 Hz to 1 MHz and 20 °C to 240 °C. Structural analysis using optical absorption and IR spectra indicated dopant ions predominantly in Cr3+, Mo6+/Mo5+, W6+ states, and occupied Td and Oh positions. Dielectric constant and conductivity were found to be the maximal for LGSMo glass, with the lowest impedance, while LGSCr glass exhibited the opposite trend. From the analysis of dipolar relaxation effects probable dipoles were identified in each glass. Studies on conductivity revealed that contribution of ionic components is very low and a substantial polaronic contribution in LGSMo glass, whereas, LGSCr glass showed a larger ionic component, specifically Li+ ion diffusion and hence more useful material for solid-state batteries with respect to the other two glasses. [ABSTRACT FROM AUTHOR]

This research delves into the influence of red lead content on the red and NIR emission characteristics of Pr3+ ions within a nonconventional antimony silicate glass system. The glasses were synthesized across a composition spectrum of (40 − x) Pb3O4‒49Sb2O3‒(10 + x)SiO2:1Pr2O3, where x ranged from 0 to 35 mol%. Characterization was carried out using XRD, DSC, XPS, and IR spectroscopy. These analyses unveiled the presence of antimony ions in both Sb3+ and Sb5+ states and lead ions in Pb4+ and Pb2+ states within these glass compositions. Optical absorption and emission spectra (at λexc = 445 nm) were recorded within the wavelength range of 400‒1800 nm. Luminescence decay profiles of two pivotal transitions, namely, 3P0 → 3F2 (red emission) and 1G4 → 3H5 (1.3 µm NIR emission), were also recorded. Various radiative parameters from these spectra were extracted using the J–O theory. The findings indicated that, as the Pb3O4 content declined from 40 to 10 mol%, the covalent nature of the samples diminished, resulting in a remarkable amplification in the intensity of both the red and NIR emission bands of Pr3+ ions. The glass containing 10 mol% of Pb3O4 exhibited the most elevated radiative parameters and quantum efficiency. This augmentation was attributed to the reduction of Pb4+ and Sb5+ ions within the glass network or the augmentation of Pb2+ ions, serving as modifiers that mitigated phonon losses. Consequently, glasses with 10 mol% Pb3O4 demonstrate great potential for telecommunications applications, owing to their significant enhancement in PL emission for the 3P0 → 3F2 and 1G4 → 3H5 transitions. [ABSTRACT FROM AUTHOR]

PbO-As2O3 glasses mixed with different concentrations of TiO2 (ranging from 0 to 1.0 mol%) were crystallized. The samples were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy (EDS) techniques. Studies were extended to optical absorption, IR, ESR, luminescence and magnetic susceptibility on these samples. The X-ray diffraction studies reveal the presence of Pb3O4, Ti(As2O7), Pb(As2O6), Pb3(AsO4)2 PbTi3O7 and Ti2O3 crystal phases. The optical absorption studies together with ESR and magnetic susceptibility measurements indicated that the titanium ions exist in both Ti3+ and Ti4+ states in all the samples and there is an increase in titanium ions in the trivalent state with increasing concentration of nucleating agent TiO2. The quantitative analysis of these results indicated that there is a growing degree of disorder in the glass network with increasing concentration of the crystallizing agent. The luminescence studies indicated that the samples crystallized with low concentrations of TiO2 show high luminescence efficiency in the visible region. [ABSTRACT FROM AUTHOR]

PbO--MoO3--B2O3 glasses containing various proportions of NiO (ranging from 0 to 1.0 mol %) have been prepared. A number of methods viz., differential thermal analysis, spectroscopic (IR and UV-Vis optical absorption, and ESR spectra) and dielectric properties (ε' tan δ, a.c. conductivity &etch;ac over a range of frequencies and temperatures) of these glasses has been employed in studies. The results of differential thermal analysis suggest a high glass forming ability for the glass containing 0.6 mol % of NiO. The studies of UV-Vis and IR spectra show that nickel ions occupy both tetrahedral and octahedral positions in the glass network with the dominance of the tetrahedral positions when the concentration of NiO is below 0.6 mol % in the glass matrix. The analysis of the results of studies of dielectric properties reveals that there is an increase in the rigidity and the dielectric breakdown strength of the glass when the concentration of NiO is around 0.6 mol %. [ABSTRACT FROM AUTHOR]

Phosphate glasses of calcium oxide have been well proved materials for various bio bones and dental implants. However, still there is a lot of scope and demand to produce efficient elastic bio implants and resource. In view of this, Zr x Ca 30-x P 70 phosphate materials are prepared by using melt quenching method. Bio, physical, thermoluminescence and elastic techniques are used to characterize the samples. Additionally, simulated body fluid was prepared and it is used especially for bio techniques. Further, the glasses are taken for different dose (~0, 10, 20 & 50 kGy) of gamma irradiation around half an hour. And again similar techniques are used to characterize the samples. All the findings from bio, physical, thermoluminescence and elastic characterization results are analysed and took for better comparison with previous studies to develop various bio bone (or) bio dental resource. Structural reports suggests that the Zr x Ca 30-x P 70 materials were glassy before immersion in SBF solution and immersed (~720 h) samples are showing partial ceramic nature. The weight loss and pH reports suggests them for alternative bio resource as a bio bones and dental implants. Observed thermal stability, microhardness and elastic modulus evaluations of Zr x Ca 30-x P 70 materials in required standards are also additional advantage. Furthermore, thermoluminiscence (TL) under different γ-irradiation doses is reported for glasses with and without immersing in a simulated body fluid. The glasses lose TL intensity when immersed in simulated body fluid for nearly 720 h. This is useful to modulate bio-behaviour in terms of hydroxyapatite layer growth on the glass surface. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigates the influence of CoO doping on concentration and characteristics of nano-sized cavities in Li₂SO₄-MgO-P₂O₅ glasses using positron annihilation lifetime spectroscopy (PALS). These defects are known to significantly impact the physical properties of glasses. Glasses with compositions of 20 Li₂SO₄-20MgO-(60- x) P₂O₅: x CoO (0 ≤ x ≤ 1.0 mol%), were prepared using melt-quench technique. PALS analysis revealed a strong dependence of positronium (e⁺- e⁻ pair) lifetime on CoO concentration. The analysis of the results further indicated that the fraction of free volume Δ f/f 0) and cavity radius (R) reached minimum values between 0.6 and 0.8 mol% CoO, but increased with further CoO doping. This suggests that cobalt ions prefer O h sites, act as network modifiers, and create a larger concentration of free volume defects when CoO is increased beyond 0.8 mol%. Notably, the PALS-derived free volume defect concentration with CoO concentration is found to follow nearly same trend exhibited by the results of optical absorption and AC conductivity studies. [ABSTRACT FROM AUTHOR]

• Sb 2 O 3 ‒Li 2 O‒MO (M=Mg, Ca & Sr): Eu 2 O 3 glasses were prepared. • Optical absorption and PL spectra were recorded. • R/O intensity ratio is the highest for SrO mixed glasses. • Reasons for enhancement are enlightened on the basis of structural variations. In this study, role of three modifier oxides (viz., MgO, CaO and SrO) on red luminescence efficiency of Eu3+ ions in Sb 2 O 3 ‒Li 2 O glass system was investigated. The absorption spectra of these glasses exhibited the bands due to 7F 0 → 5D 4 , 3 , 2 , 1 , 0 ,5G 4 , 2 , 5L 6 and 7F 0 , 1 →7F 6 transitions in the visible and NIR regions, respectively. Emission spectra recorded at λ exc =394 nm exhibited the bands due to 5D 0 →7F J (J = 0 to 4) transitions. Out of these, the band due to5D 0 →7F 2 (red emission) was found to be more intense. J-O parameters, Ω 2 and Ω 4 were evaluated using integral R/O ratio of emission spectra. Radiative parameters viz., A R , β R and σE P for Eu3+ions were calculated using J-O parameters, These parameters were observed to be the maximal for SrO mixed glasses. Variations of local symmetry and covalency in the vicinity of Eu3+ ions were found to be responsible for such larger values of these parameters and for intense red emission for SrO mixed glasses. [ABSTRACT FROM AUTHOR]

• Pb 3 O 4 mixed Li 2 O-SiO 2 :Au 2 O 3 glasses were synthesized and characterized. • Different dielectric parameters viz., ε ′ , M, Z and σ a c were measured as functions of Au 2 O 3 content. • ε′ was decreased with Au 2 O 3 upto 0.04 mol% due to growing presence of PbO 4 units. • Observed dipolar relaxation effects were evaluated using Cole-Cole diagrams. • σ a c exhibited a decreasing trend with Au 2 O 3 content up to 0.04 mol%. • Overall, the presence of red lead was found to reduce the conductivity in these glasses. Studies on dielectric properties viz., ε′ (dielectric permittivity), M, Z and σ ac as functions of frequency and temperature (over wide ranges), of glasses/glass-ceramics give quantitative information on their insulating character. Such studies are also useful for understanding structural aspects of these glasses to a great extent. In this work Pb 3 O 4 mixed Li 2 O-SiO 2 :Au 2 O 3 glasses were synthesized and heat-treated. Analysis of the results of various characterization techniques indicated increased degree of internal augmentation between various structural groups of the glass network. Observed decrease of ε′ with Au 2 O 3 content up to 0.04 mol% was attributed to the decreased magnitude of space charge polarization due to growing presence of PbO 4 units in the glass network. Dipolar relaxation effects of these samples were evaluated using Cole-Cole plots. Variation of conductivity with Au 2 O 3 concentration was analyzed using polaronic tunneling model. Conclusions of these results were found to be in in concurrence with spectroscopic studies. Overall, the presence of Pb 3 O 4 caused reduction the conductivity of these glasses. [ABSTRACT FROM AUTHOR]

• Li2O-HfO2-SiO2 glasses with fixed Sm2O3 and varied content of Au2O3 were prepared. • OA spectra exhibited a broad band in the visible region due to SPR of Au0 particles. • PL spectra of the glasses containing Au0 MPs showed a wide (sp → d) emission band. • PL spectra of Sm3+ doped glasses revealed bright orange and red emission bands. • Role of Au0 particles on improving red emission efficiency of Sm3+ ions was discussed. In this study, Li 2 O-HfO 2 -SiO 2 -Sm 2 O 3 -Au 2 O 3 glasses (doped with fixed concentration of Sm 2 O 3 and varied contents of Au 2 O 3) were synthesized and characterized. The role of Au0 particles on improvisation of red emission of Sm3+ ions was investigated. Optical absorption (OA) spectra of these glasses indicated a number of bands excited from 6H 5/2 of Sm3+ ions. A broad band in the greenish-yellow spectral region due to surface plasmon resonance (SPR) of Au0 nanoparticles was also detected in these spectra. Photoluminescence (PL) spectra of (Sm free glasses) embedded with Au0 metallic particles (MPs) showed a wide band in the visible region ascribed to the transition of electrons from sp → d energy bands. Luminescence spectra of Sm3+ doped glasses revealed bright orange and red emission bands with substantial increased intensities with increased concentration of Au 2 O 3. Effect of Au0 MPs on the red emission efficiency of Sm3+ ions was emphasized with kinetic rate equations. [ABSTRACT FROM AUTHOR]

In this work, nonlinear optical (NLO) studies of nickel oxide doped (ranging from 0.2 to 1.0 mol %) Li 2 SO 4 –MgO–P 2 O 5 glasses are reported. A combination of femtosecond (fs) laser, as a pumping light source and a high-accuracy polarimeter with low power probing laser, is used to investigate the light-induced optical anisotropy (OA) in these glass materials. The light-induced birefringence (LIB) exhibits slow relaxation tendency up to about 10 s suggesting on anisotropic photorefractive effect evidently dominated fast Kerr effect. This behavior is evaluated in the light of other results reported recently and is explained by the glass polymerization mechanisms. The photorefractive birefringence increases with increase of the quantity of NiO up to 0.8 mol% and it is attributed to the enhanced degree of depolymerization of the glass network due to the hike in the concentration of Ni2+ ions that occupy octahedral (O h) positions. Further increase of NiO content (> 0.8 mol%) causes, however, a certain decrease of the photorefractive birefringence. Notable change in concentration trend is interpreted by rising of phonon losses due to increasing portion of the nickel ions occupying tetrahedral (T h) sites that facilitates the polymerization of the glass network. The doped glasses with the NiO content of about 0.8 mol% may be considered as optimal in the sense of photorefractive efficiency. Relevant samples exhibit largest magnitudes of the photorefractive birefringence and appear to be favorable for potential applications. • Nonlinear optical (NLO) studies of NiO doped Li 2 SO 4 –MgO–P 2 O 5 glasses are studied. • Combination of femtosecond as pumping source and high-accuracy polarimeter is used. • The light-induced birefringence (LIB) exhibits slow relaxation tendency. • This behavior is explained by the glass polymerization mechanisms. • Glasses with 0.8 mol% NiO content exhibited high photorefractive efficiency. [ABSTRACT FROM AUTHOR]

• Influence of Ta2O5 on in vitro bioactivity studies of BG is investigated. • Antibacterial activity of Ta2O5-BG against S. aureus & E. coli bacteria is assessed. • XRD and SEM studies proved formation of Ta-HAp crystalline layer on the glasses. • The maximal HAp deposition is observed on BG doped with 2.5 mol% of Ta2O5. • Maximal bacterial killing effect is exhibited by BG doped with 2.5 mol% of Ta2O5. In vitro bioactivity studies (in SBF) and antibacterial activity studies (against S. aureus and E. coli bacteria) of Ta 2 O 5 doped CaF 2 ‒CaO‒B 2 O 3 ‒P 2 O 5 ‒SrO glasses were investigated. XRD and SEM studies indicated formation of Ta-HAp crystalline layer on the samples after immersing in SBF. The studies indicated the maximal content of hydroxyapatite is deposited on the surface of the glasses Ta 2.5. Antibacterial effect against E. coli and S. aureus showed that the samples doped with 2.5 mol% of Ta 2 O 5 are more efficient in killing the bacteria. Such maximal effect is attributed to the presence of the largest concentration of TaO 6 groups that have acted as modifiers in this glass sample. [ABSTRACT FROM AUTHOR]

• SeO 2 based glasses of composition 39PbO-(60- x)B 2 O 3 - x SeO 2 :1.0 Er 2 O 3 were synthesized. • IR/Raman spectra suggested growth of [SeO 3 ]2−/[SeO 4 ]2− units' ratio with SeO 2 content. • Analysis of OA spectra indicated J-O parameters to follow the order: Ω 2 > Ω 6 > Ω 4. • Green and NIR PL emission bands exhibited significant growth with SeO 2 content. • PL spectra quantitatively analysed using kinetic rate equations. • Gain co-efficient G(λ) of 4I 13/2 →4I 15/2 transition indicated its lasing behaviour. In this work we have studied impact of SeO 2 concentration on luminescence properties of 39PbO-(60- x)B 2 O 3 - x SeO 2 :1.0 Er 2 O 3 (10 ≤ x ≤ 50) glass system. The structural analysis of the samples carried out by XRD, SEM indicated that the prepared samples are in amorphous phase. IR, Raman and XPS studies revealed increasing presence of isolated selenite [SeO 3 ]2−groups and decreasing concentration of [SeO 4 ]2−(selenate) groups with increasing content of SeO 2 in the glass network. Optical absorption (OA) spectra revealed absorption bands due to 4I 15/2 → 4F 7/2 , 9/2 , 2H 11/2 , 4S 3/2 , 4I 9/2 , 11/2 , 13/2 transitions of Er3+ ions. Using J-O theory, the spectra were characterized and the evaluated Ω λ parameters are found to be in the order: Ω 2 > Ω 4 > Ω 6. The PL spectra recorded at λ exc = 378 nm exhibited the emission bands due to 2H 11/2 →4I 15/2 (B), S 3/2 →4I 15/2 (G), 4F 9/2 →4I 15/2 (O) and 4I 13/2 →4I 15/2 (NIR) transitionsof Er3+ ions. With the gradual increase SeO 2 content, the PL emission bands (especially green and NIR bands) have exhibited significant growth. The spectra were quantitatively analysed using kinetic rate equations and the causes for enhancement of PL emission were recognised and discussed. From the gain co-efficient G(λ) of the 4I 13/2 →4I 15/2 transition, its lasing behaviour is detected for a population inversion of nearly 50%. [ABSTRACT FROM AUTHOR]

• In this study concentration of defects in Li 2 SO 4 −MgO−P 2 O 5 : NiO glass system is estimated. • PAL technique with 22Na positron source (100 kBq) is used for this study. • Glass doped with 0.8 mol% of NiO found to contain maximal concentration of defects. • Higher concentration of defects is ascribed to maximal presence of O h Ni ions in this glass. • Obtained info is found to be in concurrent with inferences drawn by other studies. In this study we have evaluated the concentration of defect centers like voids, their size (up to nanoscale) and the fraction of free volume space integrated in Li 2 SO 4 −MgO−P 2 O 5 :NiO glass system as a function of NiO content. Positron annihilation lifetime (PAL) technique with 22Na positron source of radio activity 100 kBq is used for this study. The size, shape and the concentration of entrenched defects in the glass matrix are predicted to influence profoundly the physical properties of the glass. Cavity radius (R) and the entrenched free volume fraction (f v) are found to be the maximal in the sample doped with 0.8 mol% of NiO. This observation suggested that Ni2+ ions predominantly occupied octahedral positions (acted as modifiers along with SO 4 2– ions) and induced large concentration of structural defects. The obtained information is found to be in concurrent with inferences drawn from dielectrics and spectroscopic studies of these glasses reported earlier. [ABSTRACT FROM AUTHOR]

• Influence of V 2 O 5 on dielectric features of bismuth silicate glasses is investigated. • Spectroscopic studies revealed increasing disorder of the glass network with V 2 O 5 content. • σ ac exhibited maximal value for the glass with 0.6 mol% of V 2 O 5 content. • In the glasses doped with >0.3 mol% of V 2 O 5 ionic contribution to σ ac is dominant. V 2 O 5 doped lead bismuth silicate glasses were prepared by melt quenching technique. Initially, the spectroscopic investigations viz., optical absorption (OA) and EPR spectral studies were performed; the results of these studies suggested reduction of a part of V5+ ions into V4+ ions (that are identified to form vanadyl complexes viz., VO2+). The results further indicated the largest concentration of such complexes in the glass doped with 0.6 mol% of V 2 O 5. Infrared spectral (IR) results suggested a progressive disintegration of the augmented glass network with increase of V 2 O 5 concentration beyond 0.3 mol%. Later, extensive investigations on dielectric properties were carried out. Values of dielectric permittivity, ε′(ω), loss tangent and a.c. conductivity, σ ac , observed to be minimal for the glass containing 0.3 mol% of V 2 O 5 (V 3 glass) and found to be increased for further increase of V 2 O 5 content at any frequency and temperature. The electric moduli components exhibited dipolar relaxation effects. Relaxation time τ for dipoles estimated from the spectra of electric moduli showed a decreasing trend as the V 2 O 5 content increased up to 0.3 mol% and beyond that τ is found to be increased. The complexes of V4+ and Bi3+ ions with oxygen ions were predicted to be the possible dipoles responsible for the dipolar effects. A.c. conductivity variation with V 2 O 5 concentration indicated the minimum for V 3 glass and exhibited increasing trend as the content of V 2 O 5 raised from 0.3 to 0.6 mol%. Quantitative analysis of this result indicated polaronic contribution to the conductivity (ascribed to mutual transfer of polarons between V4+and V5+ ions) is prevalent in these glasses. [ABSTRACT FROM AUTHOR]