Lifetime of dynamic heterogeneity in strong and fragile kinetically constrained spin models

TL;DR

This paper investigates the lifetime of dynamic heterogeneity in kinetically constrained spin models, revealing different behaviors in strong versus fragile models and their relation to the glass transition.

Contribution

It provides a comparative analysis of dynamic heterogeneity lifetimes in strong and fragile glass-forming models, highlighting their distinct evolution near the glass transition.

Findings

Dynamic heterogeneity lifetime remains constant in strong models.

In fragile models, heterogeneity lifetime increases rapidly near the glass transition.

Results align with experimental and numerical studies of supercooled liquids.

Abstract

Kinetically constrained spin models are schematic coarse-grained models for the glass transition which represent an efficient theoretical tool to study detailed spatio-temporal aspects of dynamic heterogeneity in supercooled liquids. Here, we study how spatially correlated dynamic domains evolve with time and compare our results to various experimental and numerical investigations. We find that strong and fragile models yield different results. In particular, the lifetime of dynamic heterogeneity remains constant and roughly equal to the alpha relaxation time in strong models, while it increases more rapidly in fragile models when the glass transition is approached.