Thermal properties of glasses from the system Ag_x(As_{40}S_{30}Se_{30})_{100-x} for x=0, 0.5, 1, 3, and 5 at.% were investigated by differential scanning calorimetry. The DSC curves were obtained under non-isothermal conditions which allowed determination of the glass transition temperature T_{g} (onset temperature), crystallization temperature T_{p} (corresponding to the crystallization peak maximum), melting temperature T_{m}, crystallization enthalpy H_{c}, and melting enthalpy H_{m}. The DSC curves obtained at the same heating rate were analyzed in order to study the variation of glass transition temperature with Ag concentration. Observed T_{g} shift toward higher values, with increase in the heating rate, is in agreement with the Lasocka equation. Samples with 3 at.% and 5 at.% Ag were further thermally treated at different heating rates with the aim of analyzing kinetic processes of crystallization. The Moynihan and Kissinger models were used to calculate the activation energy of glass transition and activation energy of crystallization. For the samples that showed the crystallization processes an assessment of the thermal stability was done based on different criteria.
This paper describes the results of the determination of some thermal and structural parameters of glasses from the Cu_{x}(As_2Se_3)_{100-x} system for x=0, 1, 5, 10 and 15 at.%. Based on the differential scanning calorimetry curves taken at different heating rates, glass transition temperature T_{g}, onset temperature of crystallization T_{onset}, and melting temperature T_{m} of crystalline units formed are determined. The values of activation energy E_{g} of glass transition process are calculated. These characteristic temperatures served as the basis for the calculation of the parameters of thermal stability of the glasses towards crystallization.
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