Dynamics at the crystal-melt interface in a supercooled chalcogenide liquid near the glass transition

Abstract

Direct quantitative measurements of nanoscale dynamical processes associated with structural relaxation and crystallization near the glass transition are a major experimental challenge. these type of processes have been primarily treated as macroscopic phenomena within the framework of phenomenological models and bulk experiments. Here, we report x-ray photon correlation spectroscopy measurements of dynamics at the crystal-melt interface during the radiation induced formation of Se nano-crystallites in pure Se and in binary AsSe 4 glass-forming liquids near their glass transition temperature. We observe a heterogeneous dynamical behaviour where the intensity correlation functions g 2 (q, t) exhibits either a compressed or a stretched exponential decay, depending on the size of the Se nano-crystallites. the corresponding relaxation timescale for the AsSe 4 liquid increases as the temperature is raised, which can be attributed to changes in the chemical composition of the melt at the crystal-melt interface with the growth of the Se nano-crystallites.

Crystal Growth Kinetics in GeS2 Glass and Viscosity of Supercooled Liquid

“…On the other hand, the parameters M and N indicate a relatively fast increase in the initial crystallization rate that might be due to a secondary nucleation induced by crystal growth. , This, in combination with impingement of growing crystals, can be a plausible explanation why the standard JMA model cannot be used for the description of nonisothermal calorimetric data. Nevertheless, for a more detailed assessment of nanoscale dynamics at the crystal-melt interface, X-ray photon correlation spectroscopy seems to be promissing …”

“…Nevertheless, for a more detailed assessment of nanoscale dynamics at the crystal-melt interface, X-ray photon correlation spectroscopy seems to be promissing. 70…”