Glassy Aging Dynamics

TL;DR

This paper investigates the aging dynamics of glass formers through dielectric loss measurements, modeling the process with a modified Kohlrausch-Williams-Watts law, revealing that aging is governed by structural relaxation.

Contribution

It introduces a modified Kohlrausch-Williams-Watts law to describe aging dynamics, aligning non-equilibrium relaxation times with equilibrium measurements.

Findings

Aging dynamics follow a modified Kohlrausch-Williams-Watts law.

Aging relaxation times are consistent with equilibrium data.

Structural relaxation governs aging across frequency regions.

Abstract

We present time-dependent dielectric loss data at different frequencies for a variety of glass formers after cooling below the glass temperature. The observed aging dynamics is described using a modified Kohlrausch-Williams-Watts law, which takes into account the time-dependent variation of the relaxation time during aging. It leads to values for the aging relaxation time and stretching exponent that are fully consistent with the results from equilibrium measurements performed at higher temperatures. Irrespective of the dynamic process prevailing in the investigated frequency region, the aging dynamics is always determined by the structural relaxation process.