Structure and properties of Li+/H+ or Li+/D+ ion-exchanged aluminosilicate glasses

Non-bridging oxygen-free (NBO-free) glass of 16.7Li2O–16.7Al2O3–66.6SiO2 in mol.% is subjected to the Li+/H+ – or Li+/D+ – ion exchange at 290–300 °C using conc-H2SO4 or D2SO4 as the sources of H+ or D+, respectively. Dipping method and field-assisted one are employed for the ion exchange. Field-assisted method enables the full ion exchange without crack, and the measurements of the structure and properties are carried out on the obtained glasses. Optical absorption and the ionic conductivity change largely by the replacement of Li+ by H+ or D+. 1H–27Al and 1H–29Si CP/MAS NMR spectra show the different coupling efficiencies of H–Al and H–Si in the samples. 5-fold coordinated Al and 6-fold coordinated one appear in the glass and have strong coupling with 1H. The relation between the formation of water and the structural conversion of Al3+ ion are discussed from the point of view of the properties of the ion-exchanged glass.