In situ measurements of density fluctuations and compressibility in silica glass as a function of temperature and thermal history

TL;DR

This study uses small-angle X-ray scattering to measure density fluctuations and compressibility in silica glass, revealing how these properties depend on temperature and thermal history, and comparing different analytical methods.

Contribution

It provides new in situ measurements of silica glass compressibility across various thermal histories using two analysis methods, aligning with and extending previous research.

Findings

Compressibility values are similar in glass and supercooled liquid states.

Glass compressibility slightly decreases with higher fictive temperature.

The relaxational compressibility component aligns with prior studies.

Abstract

In this paper, small-angle X-ray scattering measurements are used to determine the different compressibility contributions, as well as the isothermal compressibility, in thermal equilibrium in silica glasses having different thermal histories. Using two different methods of analysis, in the supercooled liquid and in the glassy state, we obtain respectively the temperature and fictive temperature dependences of the isotheraml compressibility. The values obtained in the glass and supercooled liquid states are very close to each other. They agree with previous determinations of the literature. The compressibility in the glass state slightly decreases with increasing fictive temperature. The relaxational part of the compressibility is also calculated and compared to previous determinations. We discussed the small differences between the different determinations.