What is it about?

Network-forming glassy materials are part of our everyday lives, to be found in the likes of windows and smart phones, but we seldom recognise their presence until the glass cracks or shatters. Central to this issue is the glass structure, and how it responds to densification. This information is, however, difficult to find and quantify because of the inherent structural disorder in glass, the very thing that leads to the widespread utility of these materials. Here, we address these issues by investigating the densification of silica glass. This material is an archetype in which the network is constructed from n-rings, which are cyclic conformations containing n Si or O atoms.

Featured Image

Why is it important?

The n-rings were found from atomistic models that reproduce the measured diffraction results. We characterized their compaction by finding the radius of gyration and ring lifetime. The latter was calculated using an approach taken from persistent homology. We find that the glass does not densify by changing the distribution of ring sizes. Instead, ring compaction occurs, where the extent of this compaction depends on the state conditions. For example, a threshold pressure is required to produce a significant effect on compression at room temperature.

Perspectives

Our work shows that the shape of the n-rings is an important descriptor of the structure of silica and of network-forming glasses in general. Its quantification will assist in understanding how this structure responds to load and how it affects key properties such as the deformation encountered in processes such as sharp-contact loading when glass is scratched or indented.

Professor Philip S Salmon
University of Bath

Read the Original

This page is a summary of: Ring compaction as a mechanism of densification in amorphous silica, April 2023, American Physical Society (APS),
DOI: 10.1103/physrevb.107.144203.
You can read the full text:

Read

Contributors

The following have contributed to this page