Investigation of the insertion of water in hydrated layers of silicate electrode glasses

The study distinctly shows that structural changes take place in the silicate framework during the swelling process of glasses in aqueous solutions. The presence of a modified Q3 group is evidence for the exchange of protons and sodium ions; condensation reactions also take place. Using various techniques (1H NMR, infrared spectroscopy and thermal analysis) it has been demonstrated that water is present in the hydrated glass not only in the form of H2O molecules and silanol groups, but also in different structures of these two species. A molar H2O: SiOH ratio was found of approximately 1:1 (in agreement with the assumption that H3O+ ions of the solution and sodium ions of the glass are exchanged and triple bond SiOH and H2O are formed from the hydroxonium ions). (orig.)