# Thermal Conductivity of Glass-Forming Liquids

## TL;DR

This study investigates how thermal conductivity in glass-forming liquids and glasses varies with temperature, aging, and preparation methods, revealing links to structural relaxation and vibrational modes through extensive simulations.

## Contribution

It provides new insights into the dependence of thermal conductivity on aging, cooling rate, and inherent structure properties in glass-forming systems.

## Key findings

- Thermal conductivity decreases with aging near the glass transition.
- Lower cooling rates produce glasses with reduced thermal conductivity.
- Reduced conductivity correlates with less extended high-frequency vibrational modes.

## Abstract

Thermal conductivity of a model glass-forming system in the liquid and glass states is studied using extensive numerical simulations. We show that near the glass transition temperture, where the structural relaxation time becomes very long, the measured thermal conductivity decreases with increasing age. Secondly the thermal conductivity of the disordered solid obtained at low temperatures depends on the cooling rate with which it was prepared, with lower cooling rates leading to lower thermal conductivity. Our analysis links this decrease of the thermal conductivity with increased exploration of lower-energy inherent structures of the underlying potential energy landscape. Further we show that the lowering of conductivity for lower-energy inherent structures is related to the high frequency harmonic modes associated with the inherent structure being less extended.