Kinetics of the glass transition in Se72Te23Sb5 chalcogenide glass: Variation of the activation energy

The heating rate dependence of the glass transition temperature was investigated by differential scanning calorimetry (DSC) technique for the Se72Te23Sb5 glass. Different definitions of the glass transition temperature were considered. The activation energy of the glass transition was determined using different kinetic models as well as isoconversional methods. Analysis of experimental data based on Moynihan and Kissinger equations as well as using different isoconversional methods shows that the activation energy of glass transition process is not constant but varies with the degree of transformation from the glassy to the supercooled phase. The applicability and limitations of the theoretical models to describe the kinetics of the glass transition are discussed.