Influence of Density and Pressure on Glass Formation in the Kob–Andersen Model

Abstract

We systematically study glass formation in the well-known Kob–Andersen model over a wide range of densities and pressures as a basis for judging the “universality” of glass formation through a comparison to a recent systematic study of model polymeric glass-forming liquids. Our purpose is to establish general characteristics of glass formation, to identify new relations, and to discern which properties of glass-forming liquids are material-specific and which are “universal.” To this end, we analyze a number of characteristic properties of glass formation, such as the structural relaxation time, self-diffusion coefficient, viscosity, characteristic temperatures, and fragility. We also consider a suite of properties presumably related to dynamic heterogeneity in an attempt to better understand its relation to structural relaxation. We demonstrate that the glassy dynamics in the Kob–Andersen model exhibit many of the essential trends observed in polymeric glass-forming liquids, pointing to a remarkable “universality” of many aspects of glass formation.