Non-isothermal crystallization kinetics of As2Se3 glass studied by DSC

Abstract

Differential scanning calorimetry was used to study crystallization behavior in As2Se3 glass under non-isothermal conditions. The effects of changing particle size and glass-forming conditions were investigated. Based on the results of complete kinetic analysis, the crystallization kinetics was described in terms of the Johnson–Mehl–Avrami (JMA) nucleation-growth model: values of apparent activation energy and the JMA kinetic exponent were determined for all studied samples. A new conception involving the influences of the number of mechanically induced defects and amount of strains and stresses arising from the melt-quench on crystallization kinetics was introduced. The fundamental idea utilized within this conception incorporates the crucial role of both these considered factors, where the increased number of mechanical defects and heterogeneities effectively increases the number of primary nucleation centers, while the stress-induced defects originating from the glass-forming procedure seem to act as a surrogate for the secondary nucleation process participating in the growth of crystalline spherulites. Based on this novel conception, all trends and differences observable for the current data as well as for the data available in the literature were explained.