Accessing Forbidden Glass Regimes through High-Pressure Sub-T Annealing.

Density and hardness of glasses are known to increase upon both compression at the glass transition temperature (T) and ambient pressure sub-T annealing. However, a serial combination of the two methods does not result in higher density and hardness, since the effect of compression is countered by subsequent annealing and vice versa. In this study, we circumvent this by introducing a novel treatment protocol that enables the preparation of high-density, high-hardness bulk aluminosilicate glasses.

Volume and structural relaxation in compressed sodium borate glass.

The structure and properties of glass can be modified through compression near the glass transition temperature (T), and such modified structure and properties can be maintained at ambient temperature and pressure. However, once the compressed glass undergoes annealing near T at ambient pressure, the modified structure and properties will relax. The challenging question is how the property relaxation is correlated with both the local and the medium-range structural relaxation.

Pressure-induced changes in interdiffusivity and compressive stress in chemically strengthened glass.

Glass exhibits a significant change in properties when subjected to high pressure because the short- and intermediate-range atomic structures of glass are tunable through compression. Understanding the link between the atomic structure and macroscopic properties of glass under high pressure is an important scientific problem because the glass structures obtained via quenching from elevated pressure may give rise to properties unattainable under standard ambient pressure conditions. In particular, the chemical strengthening of glass through K(+)-for-Na(+) ion exchange is currently receiving significant interest due to the increasing demand for stronger and more damage-resistant glass.