Thermal analysis and physical properties of Bi–Se–Te chalcogenide glasses

Abstract

The present work reported the effect of variation of bismuth content on the glass transition, thermal stability and crystallization kinetics of Bix(Se20Te80)100−x (0⩽x⩽12) glasses. Measurements of the heat flow as a function of temperatures and different heating rates (β) for Bix(Se20Te80)100−x glasses were carried out by using differential scanning calorimetry (DSC). Both the heating rate and Bi content are found to affect the values of the characteristic temperatures such as the glass transition temperature (Tg), the peak temperature of crystallization (Tp) and the melting temperature (Tm). From the heating rate dependence of Tg and Tp, values of the activation energy for glass transition (Eg) and for crystallization (Ec) were deduced. Afify’s method was used to derive the values of Ec without any dependence on the kinetic exponent (n). The compositional dependence of Eg and Ec was discussed in terms of the chemical bond approach. Based on the values of Tg, Tp, Tm and Ec the thermal stability criteria (ΔT, Hr, Hg, S, K(T) and Kr(T)) of the studied glasses was evaluated. It was found that, increasing the Bi additions leads the decrease of the glass thermal stability i.e. the glass without any Bi content is the most stable one.