Quantitative hydrogen state analysis in the leached layer of soda-lime-silica glass by combination of nuclear reaction analysis and C60-X-ray photoelectron spectroscopy

Abstract

The effects of acid treatment on the surface layer of soda-lime-silica glasses were investigated by nuclear reaction analysis (NRA) and C60-X-ray photoelectron spectroscopy (XPS) in a depth-resolved manner. As the time of treatment with HCl increased, the amount of H increased and was distributed in a region at a depth of almost 150 nm. In the near-surface region, however, the damage due to 15N2+ beam irradiation for conducting the NRA was found to be substantial as observed by the fast decay of signal intensity with increasing ion dose. The depletion of sodium, magnesium, and calcium in the surface layer was examined by C60-XPS. Sodium was depleted at a depth of 150 nm by the acid treatment, but the depletion of magnesium and calcium occurred at a depth within approximately 30 nm. Assuming the ion exchange reaction between the alkaline and alkaline earth elements with H3O+, the Si-OH concentration profile was evaluated from the depletion profiles of sodium, magnesium, and calcium. From the difference between the Si-OH profile and H distribution obtained by NRA, the H2O/Si-OH ratio in the leached layer was estimated at 1.3.