Phase transformation and kinetic study of a Ga5Ge15Te80 chalcogenide glass using the non-isothermal method

Abstract

The crystallization kinetics for a Ga5Ge15Te80 chalcogenide glass, prepared by melt quenching technique, have been studied by differential thermal analysis (DTA) under non-isothermal condition, with five different heating rates \( \alpha = 10, 15, 20, 25\) and 30 °C/min . The DTA trace indicates the presence of two crystallization peaks. The glass transition temperature \( T_{g}\) , the crystallization temperature \( T_{c}\) and the melting point temperature \( T_{m}\) were determined. The dependence of \( T_{g}\) , \( T_{c1}\) and \( T_{c2}\) on the heating rate \( \alpha\) , were used for the determination of the activation energy of glass transition \( E_{g}\) and crystallization \( E_{c}\) . The DTA data have been analyzed in terms of activation energy, stability and dimensionality of growth (m by different models viz. Kissinger's, Mahadeavan, Augis and Bennet's and Matusita's equations. The Avrami exponents (n and (m have also been determined; the obtained values of (n and (m are 2.959 and 1.959, respectively, indicating bulk nucleation with two-dimensional growth.