On the energy landscape at the glass transition

TL;DR

This paper examines the hypothesis that the glass transition is not a distinct relaxation process but results from the breakdown of shear modulus due to elastic interactions among relaxation centers, supported by analysis of experimental data.

Contribution

It provides two theoretical derivations of the glass transition mechanism and validates one using mechanical relaxation data from various glassy materials.

Findings

Data supports the shear modulus breakdown hypothesis

Glass transition linked to elastic dipole interactions

Consistent results across multiple materials

Abstract

A recent hypothesis claims that the glass transition itself, though it is a very pronounced relaxation peak, is no separate relaxation process at all, but is just the breakdown of the shear modulus due to the weak elastic dipole interaction between all the quasi-independent relaxation centers of the glass. Two derivations are considered, one of them in terms of a breakdown of the shear modulus and the second in terms of a divergence of the shear compliance. Mechanical relaxation data from the literature for vitreous silica, glycerol, polymethylmethacrylate and polystyrene are found to be consistent with the first hypothesis.