Crystallization kinetics of chalcogenide glasses (ChG) probed via elastic vibration

Chalcogenide glasses (ChGs) have been used in industry and our daily lives as infrared optical elements. Their crystallization kinetics must be investigated because a high level of crystallinity deteriorates the optical performance of glasses. In this study, the crystallization kinetics of ChGs were investigated by using the impulse excitation technique (IET), in which crystallization kinetics was probed based on the increases in Young's modulus at an annealing temperature, T_a, higher than their glass transition temperature, T_g. It is shown that crystallization can occur at a temperature 148 °C lower than that determined based on calorimetry. The Mori-Tanaka (MT) method was employed to estimate the volume fraction of crystals under different annealing temperatures, and the activation energy of crystallization was also calculated based on the crystallization rate. This early crystallization leads to Se-rich nanocrystals with sizes well below 10 nm. They led to higher microhardness without affecting infrared transmittance. This study provides new insights for the investigation of crystallization kinetics of materials.