Investigation of Void Structure of Silica Glass using Positron Annihilation Lifetime Spectroscopy and Molecular Dynamics Simulation

Abstract

Positron annihilation lifetime spectroscopy (PALS) is a powerful technique in the characterization of void sizes in various kinds of materials. In this work, silica glasses with different fictive temperatures (T_f) were investigated using PALS. Although the density of silica glass is well known as to increase – so that the space is supposed to decrease - with higher T_f, voids were observed to expand. Considering the results of molecular dynamics (MD) simulations, a picture of structure and voids and its temperature dependence in silica glass will be proposed.