Nonmonotonic evolution of density fluctuations during glass relaxation

A fundamental understanding of glass relaxation behavior is vital to the glass and polymer science communities. While prior work has focused on relaxation of first-order thermodynamic properties such as enthalpy and density, we present theoretical and experimental results showing that fluctuations in enthalpy and density relax nonmonotonically. These results provide direct evidence for dynamical heterogeneities and their close association with density fluctuations. Our results imply that density fluctuations, and hence light scattering, can be minimized through design of thermal history.