Atomic understanding of the densification removal mechanism during chemical mechanical polishing of fused glass

The numerous voids inside fused glass makes it extremely susceptible to densification during processing, which dramatically impedes the application of fused glass. Up to now, it is still a huge challenge to elucidate the densification removal mechanism of fused glass. Herein, we established the local densification of fused glass based on friction-induced densification, and mimicked the chemical mechanical polishing (CMP) process via ReaxFF molecular dynamics (MD). The discrepancy between densified area (DA) and non-densified area (NDA) was investigated, and the densification damage mechanism was elaborated from the atomic scale. The results showed that the high atomic density in DA hindered the oxidation reaction and weaker the hydrophilicity. Less of Si-OH bonds were formed on the surface, and the penetration of H protons was also weakened. Under low pressure, the atoms were efficiently removed in form of short chain and single atoms without the deterioration of the densification. Nonetheless, under high pressure, the atoms were efficiently removed in form of chain, cluster and ring removal with the deterioration of the densification. Moreover, the deterioration of the densification was inhibited with the increasement of H2O2 concentration. Our simulations provide new insights for fused glass densification studies from an atomic perspective.