Revealing the structure of the sodium-leached layer of soda lime silica glass: A comprehensive spectroscopic analysis

Acid treatment of soda lime silica glass results in incongruent leaching of sodium from the surface, with minimal dissolution of the silicate network or the other cationic network modifiers. The structure of this sodium-leached region was probed using nanoscale-FTIR and Raman spectroscopy. After accounting for interfacial interference, the resultant spectra were compared with molecular dynamics simulations to connect the observed spectral changes to the structure. This comparison showed that the correlations between spectral features and bond parameter distributions derived from the melt-quench formed glass can also be applied to a chemically-modified glass. Additionally, the IR active shoulder at ∼950 cm^-1 which was traditionally attributed to the non-bridging oxygen stretch mode, was confidently correlated to perturbations in the silicate network which results from the network modifiers which charge compensate those non-bridging oxygen. The decrease in this spectral feature after acid treatment then corresponds to localized structural relaxations as the glass network becomes more silica-like.