Microscopic and thermodynamic origins of volume relaxation in soda-lime aluminosilicate glasses below the glass transition temperature

The microscopic and thermodynamic features of structural relaxation below the glass transition temperature are still major unsolved problems in the field of glass science. In this study, we used both experimental and theo-retical approaches to elucidate the role of non-bridging oxygens in the volume relaxation of soda-lime alumi-nosilicate glasses below the glass transition temperature. Both approaches yielded similar trends, with greater shrinkage observed for glasses with a higher number of non-bridging oxygens. Based on our findings, we pro-posed and validated a theoretical equation for determining the volume relaxation time. Molecular dynamics simulations also suggested that volume relaxation is affected by the stericity of the rings in the glass network.

Automated summary

The role of non-bridging oxygens in the volume relaxation of soda-lime aluminosilicate glasses below the glass transition temperature was investigated using experimental and theoretical approaches. The results showed that glasses with a higher number of non-bridging oxygens exhibited greater shrinkage. A theoretical equation for determining the volume relaxation time was proposed and validated. Molecular dynamics simulations also revealed that the stericity of the rings in the glass network affects volume relaxation.