Iso-conversional analysis of thermally induced glass transition in some quaternary glasses of SeTeSnGe system

Abstract

The study of glass transition and its consequences is an essential task to decide the utility of glasses (ChGs) at the industrial level. The model fitting non-isothermal methods provide information about the glass transition in terms of the related overall activation energy. However, thermal analysis of the activation energy at the different extent of conversions reveals the features of glass transition more deeply as compared to the non-isothermal model-fitting methods. Keeping in mind this fact, we have studied the iso-conversional glass transition in Se78-xTe20Sn2Gex (STSG ChGs, x = 0, 2, 4, and 6) glasses using calorimetric experiments in Differential Scanning Calorimetry (DSC).The temperature dependence of the extent of conversion (i.e., glass transition fraction αg) and the variation of activation energy Eg and rate constant with αg have been studied. Further, the various heating rate method has been chosen to study the correlation between the iso-conversional rate constant and corresponding activation energy. The variation of Eg with αg for the present samples of Se78-xTe20Sn2Gex indicates the occurrence of the rigidity transitions after x = 2 because of the abrupt growth in the number density of edge-sharing tetrahedral species of GeSe4 over the corner-sharing species.