Approximate square-root-time relaxation in glass-forming liquids

TL;DR

This study shows that the primary dielectric relaxation in most glass-forming liquids closely follows a square-root-time pattern, challenging previous beliefs and indicating a universal behavior across diverse liquids.

Contribution

The paper provides extensive empirical evidence that square-root-time relaxation is a common feature of the alpha process in glass-forming liquids, contradicting prior assumptions.

Findings

Square-root-time relaxation is prevalent in most glass-forming liquids.

Better inverse power-law fits correlate with more accurate square-root-time relaxation.

Deviations occur mainly in liquids with very large dielectric losses.

Abstract

We present data for the dielectric relaxation of 43 glass-forming organic liquids, showing that the primary (alpha) relaxation is often close to square-root-time relaxation. The better an inverse power-law description of the high-frequency loss applies, the more accurately is square-root-time relaxation obeyed. These findings suggest that square-root-time relaxation is generic to the alpha process, once a common view, but since long believed to be incorrect. Only liquids with very large dielectric losses deviate from this picture by having consistently narrower loss peaks. As a further challenge to the prevailing opinion, we find that liquids with accurate square-root-time relaxation cover a wide range of fragilities.