Toward a Better Understanding of Activation Volume and Dynamic Decoupling of Glass-Forming Liquids under Compression

Physical properties of the pressure-induced activation volume and dynamic decoupling of ternidazole, glycerol, and probucol by the elastically collective nonlinear Langevin equation theory is theoretically investigated. Based on the predicted temperature dependence of activated relaxation under various compressions, the activation volume is determined to characterize effects of pressure on molecular dynamics of materials. It is found that the decoupling of the structural relaxation time of compressed systems from their bulk uncompressed value is governed by the power-law rule. The decoupling exponent exponentially grows with pressure below 2 GPa. The decoupling exponent and activation volume are intercorrelated and have a connection with the differential activation free energy. Relationships among these quantities are analyzed numerically and mathematically to explain many results in previous experiments and simulations.

Automated summary

In this study, the physical properties of ternidazole, glycerol, and probucol under pressure-induced activation volume and dynamic decoupling were theoretically investigated. The study found that pressure affects the molecular dynamics of materials and decouples the structural relaxation time of compressed systems from their uncompressed value. The decoupling exponent and activation volume are intercorrelated and linked to the differential activation free energy, providing explanations for results in previous experiments and simulations.