Characterization of surface structures of dealkalized soda lime silica glass using X-ray photoelectron, specular reflection infrared, attenuated total reflection infrared and sum frequency generation spectroscopies

This paper reports a comprehensive spectroscopic characterization of soda lime silica (SLS) glass surfaces with various thermal histories and dealkalization chemical treatments. While many studies have investigated elemental composition changes after dealkalization treatments, the work reported here focuses on identification and quantification of the associated structural changes in terms of non-bridging oxygen (NBO), bridging oxygen (BO) and hydrous species (Si–OH and H₂O). X-ray photoelectron spectroscopy (XPS) was used to determine the average areal densities of BOs, NBOs, and OH groups at the top 10 nm of the surface. Specular reflection infrared (SR-IR) spectroscopy was used to probe the Si–O–Si asymmetric stretch vibration mode of the silicate network of the top < 700 nm of the surface. Attenuated total reflection infrared (ATR-IR) spectroscopy was used to compare the amount of hydroxyl and molecular water in the glass sub-surface. Vibrational sum frequency generation (SFG) spectroscopy was used to probe hydrogen bonding interactions of molecular water adsorbed onto the glass surface and hydrous species trapped in the sub-surface. The synergy of these characterization techniques has been shown to provide quantitative structural information of silicate glasses with various thermal histories and chemical dealkalization treatments.