Relationship between non-exponentiality of relaxation and relaxation time at the glass transition

TL;DR

This paper reveals a unique relationship between non-exponential relaxation behavior and relaxation time at the glass transition, supported by experimental data and a theoretical elasticity-based approach.

Contribution

It establishes a novel quantitative relationship between relaxation non-exponentiality and relaxation time in glass-forming liquids and polymers.

Findings

Logarithm of relaxation time is linearly related to inverse non-exponentiality parameter.

A crossover to a higher linear slope occurs in the relationship.

Theoretical explanation based on elasticity approach supports the empirical findings.

Abstract

By analyzing the experimental data for various glass-forming liquids and polymers, we find that non-exponentiality $\beta$ and the relaxation time $\tau$ are uniquely related: $\log(\tau)$ is an approximately linear function of $1/\beta$, followed by a crossover to a higher linear slope. We rationalize the observed relationship using a recently developed approach, in which the problem of the glass transition is discussed as the elasticity problem.