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A series of fluorotellurite glasses based on 70TeO2-5MxOy-10P²O5-10ZnO-5PbF2 in mol%, where MxOy = (WO3, Nb2O5) doped with 2400 ppm of Er2O3 have been prepared by the conventional melt quenching method. The influence of modifiers on thermal and optical properties of glasses has been analyzed. Thermal characteristics of glasses like the glass transition temperature Tg, the temperature for the crystallization onset Tx, the maximum crystallization temperature Tc, and the thermal stability parameter were determined by the DSC method. The ellipsometric data have provided Sellmeier-type dispersion relations of the refractive index of the investigated glasses. The optical parameters are used to calculate the molar refractivity, molar polarizability, oxide ion polarizability, molar cation polarizability, and a number of polarizable atoms per unit volume for every glass composition in order to interpret the refractive index of these glasses. [ABSTRACT FROM AUTHOR]

We have investigated the spectroscopic properties of Er3+-doped fluorotellurite glasses with the basic molar composition 75%TeO2-10%P2O5-10%ZnO-5%PbF2, modified by replacing 5% TeO2 by a metal oxide, namely WO3 or Nb2O5. The absorption edge of the glasses studied has been described within the Urbach approach, while the absorption and photoluminescence spectra have been analyzed in terms of the standard Judd-Ofelt theory, along with the photoluminescence decay of the 4I13/2 and 4S3/2 levels of the Er3+ ion. The absorption and emission spectra of the 4I15/2 ↔ 4I13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit for the amplifier gain. It appears that the fluorotellurite glass containing WO3 as a modifier is characterized by the largest figure of merit, indicating this matrix as a promising new host for doping with Er3+ ions. [ABSTRACT FROM AUTHOR]

We have investigated the spectroscopic properties of Er3+-doped fluorotellurite glasses with the basic molar composition 75%TeO2-10%P2O5-10%ZnO-5%PbF2, modified by replacing 5% TeO2 by a metal oxide, namely WO3 or Nb2O5. The absorption edge of the glasses studied has been described within the Urbach approach, while the absorption and photoluminescence spectra have been analyzed in terms of the standard Judd-Ofelt theory, along with the photoluminescence decay of the 4I13/2 and 4S3/2 levels of the Er3+ ion. The absorption and emission spectra of the 4I15/2 ↔ 4I13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit for the amplifier gain. It appears that the fluorotellurite glass containing WO3 as a modifier is characterized by the largest figure of merit, indicating this matrix as a promising new host for doping with Er3+ ions. [ABSTRACT FROM AUTHOR]

A neodymium (Nd3+) doped oxyfluoride glass ceramics containing SrF2, LaF3 nanocrystals has been presented. Transparent glass ceramics was obtained by heat treating the glass from the SiO2--Al2O3--ZnO--Na2O--SrF2 and SiO2--Al2O3--ZnF2--Na2O--LaF3 system at the first crystallization temperature. Cerammization of glass was studied by DTA/DSC, XRD. It has been found that nanocrystallization of SrF2 and LaF3 strongly depends on the ratio between the components and the amount of SrF2 and LaF3, respectively. The optical studies of the glasses comprised spectrophotometry (reflectance and transmittance) and spectroscopic ellipsometry. The spectrophotometric measurements yield a number of narrow absorption bands which correspond to characteristic transitions between the ground- and consecutive excited states of rare earth ions. Growth luminescence at typical neodymium wavelength was observed under diode laser (808 nm) excitation in glass ceramics with SrF2 in comparison to parent glass. The optimization of cerammization process allowed to fabricate the oxyfluoride glass ceramics optical fibre with strong emission originated from Nd3+ ions. The influence of the cerammization process on the changes in the refractive index of glass was examined. [ABSTRACT FROM AUTHOR]

The influence of nanocrystallization process in oxyfluoride glasses Na2O-Al2O3-SiO2-LaF3-NaF doped with rare earth (RE) ions on their thermal and optical properties is studied. The thermal characteristics of oxyfluoride glasses (OG) with Tm3+, Yb3+ are presented. The effect of the glass crystallization on thermal stability of the glass and crystallizing phases formed upon heat treatment is investigated by DTA/DSC and XRD methods. It has been found that the effect of nanocrystallization of LaF3 and incorporation of RE elements in formed upon heat treatment nanocrystallites depends on the kind of rare earth elements and is determined by factors of crystallochemical nature and requires adequate proportions between the components forming glass structure. The ellipsometric investigations are performed by M2000 spectroscopic ellipsometer. These measurements allowed us to determine dispersion of refractive indices in the range 190-1700 nm and depolarization coefficients. The influence of nanocrystallization process on refractive indices is discussed. [ABSTRACT FROM AUTHOR]

The goal of the work was to characterize and synthesize tellurite glasses from the TeO2-WO3-PbO-La2O3 system. The effect of lanthanum oxide content on the tendency to the crystallization of glassy matrix was investigated. Differential thermal analysis DTA/DSC, XRD measurement were considered in terms of the lanthanum oxide influence. Presented work is a continuation of investigations of tellurite glasses with use of the Faraday effect method. The Faraday effect is a rotation of polarization of linearly polarized light in an isotropic transparent material under the magnetic field. It has been stated that the addition of lanthanum to tellurite glass from the TeO2- WO3-PbO system hinders the crystallization process of glass which is very important during fiber drawing. Tellurite glasses have physical and chemical properties that make this class of materials a potential candidate in different applications, such as electrochemical and optoelectronic devices. In the field of photonics these glasses may be used as precursors for infrared fibers or windows due to the possibility of changing their phonon energies and therefore the domain of wavelength transparency as a function of compositions. [ABSTRACT FROM AUTHOR]

The paper presents new glass-ceramics as a material for up-conversion luminescence. Formation of the LaF3 nanocrystals have been obtained as a low phonon host for rare earth active ions in oxide glassy matrix. The thermal conditions of LaF3 nanocrystallization in the glass from the SiO2-Al2O3-Na2O-LaF3 system have been presented. Transmittance and luminescence properties as a function of heat treatment have been investigated. The effect of incoming of Er3+ in LaF3 crystals has been shown on the luminescence properties. AFM results have confirmed the growth of nano-scale crystals. [ABSTRACT FROM AUTHOR]

Tests on glass texture were made in order to establish the size of porous space in modified glasses Al2O3 from the system Na2O-B2O3-SiO2 after extraction of dissolved boron phase during chemical treatment. A difference was observed in the size and volume of mezo- and micropores in 0.6% and 0.3% Al2O3 glasses depending on temperature of heating. Accounting for the difference of glass structure attempts were made to use them for the selective sorption of hydrocarbons dissolved in water. It follows from the obtained results that differences in hydrocarbon removal are as much as tens of percent. The efficiency of removal is conditioned by the type of glass and grain size of glass applied for sorption. [ABSTRACT FROM AUTHOR]