Thermal characterization of Se100−xSnx (x = 4, 6 and 8) chalcogenide glasses using differential scanning calorimeter

Abstract

Thermal studies of Se100−xSnx (x=4, 6 and 8) glasses were carried out using differential scanning calorimeter (DSC) under non-isothermal condition. Well defined endothermic and exothermic peaks were observed in the glass transition and crystallization regions, respectively. From the dependence of the glass transition temperature (Tg) on the heating rate (β), the relaxation activation energy (Et) was calculated using Kissinger and Moynihan methods. Results reveal that Et increases with an increase in Sn content which indicates that thermal stability is retarded. This is attributed to the corresponding increasing in cohesive energy of the glasses when SeSe bonds replaced by SeSn stronger bonds. In addition, the variation of the crystallization peak temperature (Tp) with the heating rate (β) was utilized in determination of the crystallization activation energy (Ec) and Avrami exponent (n). Ec values were calculated using Kissinger and Augis–Bennett methods, while n values were estimated using Augis–Bennett and Ozawa–Matusita methods. Besides, the average value of crystallization rate factor <Kp> was calculated using the model suggested by Gao and Wang. The values of Ec and <Kp> were found to decrease with increasing Sn content. Meanwhile, the crystal growth in the present binary alloys was found to occur in one dimension.