Rate equations for cluster formation in supercooled liquids

TL;DR

This paper introduces rate equations with physically derived coefficients to model cluster formation in supercooled liquids near the glass transition, offering insights into the differences between strong and fragile liquids and the nature of the glass transition.

Contribution

It presents a novel approach to modeling cluster formation using rate equations with physically based coefficients, avoiding thermodynamic parameters.

Findings

Rate equations produce physically reasonable results for supercooled liquids.

Differences between strong and fragile liquids relate to surface molecule binding strength.

Insights into the glass transition and glass structure are provided.

Abstract

The formation of clusters in supercooled liquids close to the glass transition temperature is described by rate equations in which the coefficients are determined on physical grounds rather than in terms of thermodynamic quantities such as free energies and surface tensions. In particular, the density of free molecules in the liquid as a function of temperature is determined self-consistently. Calculations for a very simple model indicate that such rate equations are capable of producing physically reasonable results. Our results suggest that the difference between strong and fragile liquids may be associated with the strength of the binding of a surface molecule to a cluster, and they also provide indications about the nature of the glass transition and the structure of the resulting glass.