Topic: Glass relaxation above and below Tg: The shoving model and single-parameter aging

Lecturer: Professor Jeppe C. Dyre

Time: December 17th, 2025, 10:00 UTC+8

Venue: Room 502, Silicate New Building

Biography: Dyre Jeppe C. Dyre is Professor of Physics at Roskilde University, Denmark, and a member of the Royal Danish Academy of Sciences and Letters. He founded and led the “Glass and Time” research center funded by the Danish National Research Foundation, serving as Director of the Danish National Research Foundation Center (DNRF) for “Glass and Time” from 2005 to 2015. His research focuses on investigating viscous liquids and the glass transition, the dynamics of disordered solids, ion conduction in glasses, and theories of nonlinear response, integrating perspectives from mathematics, statistical physics, rheology, and computational simulation. His work has advanced the theoretical understanding of the glass transition and rheological behavior, while also offering insightful perspectives on aging dynamics, energy landscapes, and structure-dynamics coupling.

Abstract: This talk reviews two mathematically simple models of possible general validity for glass-forming liquids. The shoving model for the relaxation time’s temperature dependence above Tg states that the activation energy is proportional to the high-frequency shear modulus. This quantity increases when temperature is lowered, providing a possible explanation of the ubiquitous non-Arrhenius temperature dependence. Single-parameter aging is simplification of the half-century old Narayanaswamy formalism of aging, which is based on the intriguing concept of a material time. Both models are compared to experimental data, primarily on simple molecular liquids.

Rewritten by: Li Huihui

Edited by: Li Tiantian

Source: State Key Laboratory of Silicate Materials for Architectures