Investigations Of Glass Corrosion In Acid Solutions With 29Si-Mas-Nmr

Thin foils of potash-lime-silicate glass were corroded in acid solutions for different time periods. The formation of a gel layer was determined by IR spectroscopy and solution analysis. The applicability of 29Si-MAS-NMR spectroscopy as an analytical tool for characterising gel layers was investigated. The obtained spectra of increasingly corroded foils show the growth of a new peak at the highfield side of the main glass peak. This peak can be attributed to Q4 silicon units. The formation of Q4 silicon is believed to be due to a condensation reaction of previously hydrolysed Si-OH groups in the gel layer.