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Abstract: Differential scanning calorimetry (DSC) measurements were performed to investigate the kinetics of the structural relaxation in aged and unaged (rejuvenated) As x Se100−x glasses with 0≤x≤40. The activation energy of the glass transition (E a ) of the aged and rejuvenated glasses was determined from the variation of the glass transition temperature (T g ) with the heating rates (β). Significant effect of prolonged aging of the glasses on the values E a was observed. Evidence of transition from floppy to rigid phase is presented. The observed significant physical aging in samples with composition x<40 indicates the absence of the intermediate phase. The compositional dependence of T g for aged and rejuvenated data was analyzed using the stochastic agglomeration theory. [Copyright &y& Elsevier]

Abstract: Differential scanning calorimetry (DSC) technique was used to study the kinetics of amorphous to crystalline transformation in Pb4.3Se95.7 chalcogenide glass. Non-isothermal measurements were performed at different heating rates (5–60K/min). The activation energy of crystallization was determined by analyzing the data using Matusita et al. method. A strong heating rate dependence of the activation energy was observed. The isoconversional methods of Kissinger–Akahira–Sunose (KAS) and Vyazovkin confirm that the activation energy of crystallization is not constant but varies with the degree of crystallization and hence with temperature. This variation indicates that the transformation from amorphous to crystalline phase in Pb4.3Se95.7 is a complex process involving different mechanisms of nucleation and growth. [Copyright &y& Elsevier]