Direct visualization of aging in colloidal glasses

TL;DR

This study employs confocal microscopy to directly observe how colloidal glasses age, revealing spatial and temporal heterogeneity in particle dynamics and the continuous occurrence of particle motions across all time scales.

Contribution

It provides the first direct visualization of aging processes in colloidal glasses, highlighting heterogeneity and persistent dynamics during aging.

Findings

Particle motion slows as the sample ages

Aging is spatially and temporally heterogeneous

Relaxation time increases with age but particle motions persist

Abstract

We use confocal microscopy to directly visualize the dynamics of aging colloidal glasses. We prepare a colloidal suspension at high density, a simple model system which shares many properties with other glasses, and initiate experiments by stirring the sample. We follow the motion of several thousand colloidal particles after the stirring and observe that their motion significantly slows as the sample ages. The aging is both spatially and temporally heterogeneous. Furthermore, while the characteristic relaxation time scale grows with the age of the sample, nontrivial particle motions continue to occur on all time scales.