Anomalous Thermomechanical Properties Of Network Glasses

Anomalous thermomechanical behaviours of silica glass, which include negative thermal expansion and the increase of elastic moduli with decreasing density, have been known for some time, but no satisfactory explanation has been available. Recent advances in measurement technology and computational means for interpreting the observed behaviours have allowed improved understanding of these phenomena. This paper presents experimental data showing that anomalous temperature dependencies of mechanical properties are common to all strong network glass formers, and that they extend into the liquid state. Furthermore, based on atomic-scale computer simulations, an explanation is provided for the anomalous properties of silica.