An artificial dynamic heterogeneity in a glass-former below Tg

TL;DR

This study uses large-scale molecular dynamics simulations to demonstrate that photoisomerization of probe molecules induces artificial dynamical heterogeneity and enhances diffusion in a glassy material below Tg, aligning with experimental observations.

Contribution

It introduces the first large-scale simulation showing how photoisomerization creates artificial heterogeneity and increases diffusion in glassy materials below Tg.

Findings

Photoisomerization induces artificial dynamical heterogeneity.

Significant increase in diffusion below Tg due to photoisomerization.

Heterogeneity and non-Gaussian parameters are rapidly modulated by photoisomerization.

Abstract

We report the first large scale molecular dynamics simulations of the effect of the photoisomerization of probe molecules on the dynamics of a glassy molecular material. We show that the photoisomerization of the probe molecules induces the creation of an artificial dynamical heterogeneity inside the matrix. We then study the modification of the dynamics and find, in agreement with recent experiments, an important increase of the diffusion leading to liquid like diffusion below the glass transition temperature. We find that the photoisomerization process controls the heterogeneity and the non-Gaussian parameter of the material, leading to extremely rapid variations of these quantities.