[en] The data on crystallization of chalcogenide glasses in the systems of As-Se-Te, Ge-Se-Te, etc. are reviewed. The available data on the effect of composition and degree of purity of glasses on their stability to crystallization are considered. The stability to crystallization is compared on the basis of known criteria: the critical cooling rate, the Tc-Tg interval between the values for temperature of crystallization Tc and of glass-formation Tg determined by differential thermal analysis

[en] Crystallization kinetics of glass in system ZrF₄-BaF_2LaF₃-AlF₃-LiF (ZBLALi) at early stages of ''glass-crystal'' transformation in the temperature range of 240-380 deg C is investigated. Results of investigation of nucleation rate and crystal growth linear rate for the range 240-310 deg C are given. It is shown that lower rate of crystal growth in glass of the ZBLALi system in the the range above 280 deg C is explained by the fact that surface crystallization in samples of the glass starts at temperature exceeding 300 deg C

[en] An analysis of the results of measurements by using the pump – probe method with a femtosecond resolution in time and computer simulation of the charge carrier kinetics have revealed two types of a nonlinear optical response in samples of chalcogenide glasses belonging to the As – S – Se system, irradiated by 50-fs laser pulses with a wavelength of 0.79 μm. The difference in the nonlinear dynamics is due to the difference in the photoexcitation character, because laser radiation can be absorbed either through bound states in the band gap or without their participation, depending on the ratio of the pump photon energy to the bandgap energy. (nonlinear optical phenomena)

[en] Crystallization kinetics for fluorozirconate glass of the ZrF₄-BaF₂-LaF₃-AlF₃-NaF system is investigated. The rate of nucleation in the temperature interval from 240 to 310 deg C and linear velocity of crystal growth in the range from 240 to 380 deg C are determined. The part of a crystalline phase is calculated from the concentration and sizes of crystallites determined by the method of laser ultramicroscopy

[en] Short note

[en] Glass materials with high emission characteristics and low content of limiting impurities are required for creation of devices for middle infrared (mid-IR) fiber optics. The paper presents the results of preparation of high-purity Pr³⁺-doped Ga_xGe_ySb_zSe_1−(x+y+z) (x=3÷4, y=20÷26, z=5÷11) glasses. The multi-stage technique for synthesis of these glasses is developed. It is based on chemical distillation purification of glass components and the transport reaction for purification of gallium. Transmitting, as well as thermal and luminescent properties of glasses are investigated. The content of limiting impurities of oxygen, carbon and hydrogen in the glass samples was ≤0.2 ppm wt. The 1300–3000 ppm wt Pr³⁺-doped Ga–Ge–Sb–Se bulk glasses exhibit an intensive photoluminescence in the spectral range of 3.5–5.5 μm.

[en] The multi-stage method for the synthesis of high-purity Ge–As–Se–In–I glasses doped with Pr³⁺ ions is developed. It is based on the chemical distillation purification of glass-forming melt and the chemical transport reactions for purification and vacuum loading of indium. The level of purity of glasses, synthesized by this method, is higher in comparison with the traditional direct melting method for glass synthesis. The high-purity Pr³⁺-doped Ge–As–Se–In and Pr³⁺-doped Ge–As–Se–In–I glass samples are prepared; the optical, thermal and luminescent properties are investigated. The purest host glass samples, obtained by the multi-stage purification techniques, contain a low concentration of limiting impurities: hydrogen − ≤0.05 ppm (wt) and oxygen − ≤0.1 ppm (wt), that is, at present, the best result for multi-component chalcogenide glasses for mid-IR active fibers. The samples of Pr³⁺-doped Ge–As–Se–In glass fibers have the minimum optical losses of 0.58 dB/m at the wavelength of 2.72 μm and exhibit an intense broadband luminescence in the spectral range of 3.5–5.5 μm, with a maximum shifted to longer wavelengths as compared with the bulk samples.

[en] The effect of phase purity of glass ZrF₄-BaF₂-LaF₃-AlF₃-NaF on the nucleation rate W and the linear growth rate of crystals V has been studied. The temperature dependence W(T) and V(T) was found for two specimens of glasses of the same composition with different initial content of the scattering centers. Kinetic parameters of crystallization are sensitive to initial content of phase heterogeneities in glass

[en] The behavior of the carbon admixture particles in tellurium by its refining through vacuum distillation is studied. It is shown, that the values of the separation effective coefficient for the particles depend on the evaporation rate and particles size. The peculiarities of the carbon particles behavior by the tellurium distillation are conditioned by the melt increased viscosity and ability for the particles reverse sedimentation in liquid tellurium. The account for these peculiarities is necessary to provide for the tellurium effective refining from the particles during its vacuum distillation and by determining the separation effective coefficient

[en] Glosses of the Ga-La-S system, alloyed with praseodymium, are synthesized. The crystallization kinetics of glass of the (Ga₂S₃)_0.7(La₂S₃)_0.3 with addition of 5x10^-2 mass % Pr₂S₃ by small values of glass transformation rate into crystal phase is studied. The temperature dependence of nucleus formation and linear velocity of crystals growth in the area of 770-930 K is investigated