Abstract
The effect of thermal history on cold crystallization and glass transition in glassy Se and Se90Te10 was studied using differential scanning calorimetry (DSC) technique. The amorphous Se and Se90Te10 materials were prepared using standard melt quench technique. The aged samples were stored in the dark for prolonged period of time (similar to 5 years) at room temperature. All samples were thermally treated to remove thermal history using a rejuvenated procedure and then the same kinetic parameters were determined. A significant shift of the glass transition temperature along with the large endothermic signal was observed indicating of the important effect of thermal history on glass transition. No such effect was observed in the crystallization exothermic peaks. The activation energies for glass transition and crystallization thermal events in glassy Se and Se90Te10 were determined using Moynihan et al and Ozawa methods, respectively. It is found that the activation energy for glass transition decreases with aging in both glasses. The pronounced changes observed in the characteristics of the glass transition in aged samples as compared to the rejuvenated samples are due to structural relaxation of the glassy phase.