Equilibrium and out of equilibrium thermodynamics in supercooled liquids and glasses

TL;DR

This paper reviews the thermodynamical formalism for supercooled liquids and glasses, proposing a generalized equation of state applicable to both equilibrium and aging out-of-equilibrium conditions based on potential energy surface analysis.

Contribution

It introduces a generalized thermodynamic framework that extends equilibrium equations of state to out-of-equilibrium supercooled liquids and glasses using potential energy minima.

Findings

Derived an equation of state for liquids in equilibrium.

Extended the formalism to describe aging out-of-equilibrium states.

Introduced a new parameter related to local minima for out-of-equilibrium conditions.

Abstract

We review the inherent structure thermodynamical formalism and the formulation of an equation of state for liquids in equilibrium based on the (volume) derivatives of the statistical properties of the potential energy surface. We also show that, under the hypothesis that during aging the system explores states associated to equilibrium configurations, it is possible to generalize the proposed equation of state to out-of-equilibrium conditions. The proposed formulation is based on the introduction of one additional parameter which, in the chosen thermodynamic formalism, can be chosen as the local minima where the slowly relaxing out-of-equilibrium liquid is trapped.