Pressure-induced structural transformations at different length scales in soda-lime silica glasses

Despite the widespread use of soda-lime silica (SLS) glasses, their short-range order (SRO) and especially medium-range order (MRO) structures are still not fully understood. In this work, we study the effect of pressure quenching on the structure of SLS glasses. Our analyses are based on atomic configurations established through classical molecular dynamics simulations. We characterize the SRO through analysis of coordination numbers, Qⁿ speciation, and bond angle distributions, while we identify the MRO signatures using persistent homology and classical ring analysis to capture both chemically and non-chemically bonded rings. We also analyze the MRO signatures by analyzing the voids identified by persistent homology. We find that the densification results in an increase in both Si and O coordination number and altering bond angles. Considering MRO length scales, the position of the first sharp diffraction peak shifts to higher Q values while its intensity decreases with pressure. Additionally, we identify smaller voids and loops as well as tetrahedral and pentahedral symmetries in the densified glasses. Overall, our work offers insights into the densification mechanism of SLS glasses.