Solid state Al-27 NMR and FTIR study of lanthanum aluminosilicate glasses

The structure of lanthanum aluminosilicate (LAS) glasses, containing: (15-2 5) mol% La2O3, (15-35) mol% Al2O3 and (40-70) mol% SiO2, were studied by Al -27 nuclear magnetic resonance (NMR) and Fourier transform infrared spectro scopy (FTIR). The effects of La2O3 and Al2O3 content on the properties and structure of the LAS glasses were evaluated. Al3+ ion enters into the glass structure mainly in fourfold co-ordination, forming (AlO4/2)(-) tetrahedra , and only in small amounts in fivefold and sixfold co-ordination. La3+ act s as network modifier, producing more non-bridging oxygen atoms as its cont ent increases. (C) 1999 Elsevier Science B.V. All rights reserved.