Reaction of soda lime silicate glass in isotopically labelled water

Soda lime silicate galss was leached in D 18 2O at 25, 50, and 90°C up to 500 h and was examined using non-resonant nuclear reaction and Rutherford Backscattering analysis. Replacement of sodium by deuterium ( D/ Na = 2.3 ±0.5) was consistent with earlier results, which have been cited as support for an ion-interdiffusion leaching mechanism. However, uptake of 18O was in excess of D ( 18 O/D = 1.6±0.3 ), with 18O penetrating to depths as great as those from which Na was extracted. Results indicate extensive hydrolysis and condensation reactions of the silicate matrix within the surface reaction layer while alkali is being extracted, an example of a “transformed” surface structure through which water has relatively easy access.