Materials Research Bulletin, Vol.32, No.6, 679-687, 1997
A B-11 and Li-7 MAS-NMR Study of Sol-Gel Lithium Triborate Glass Subjected to Thermal Densification
The effects of thermal densification on a sol-gel lithium triborate glass have been studied by B-11 and Li-7 NMR both static and at the magic angle (MAS). B-11 spectra show that the boron average coordination is similar in sol-gel and melt-quenched samples and it does not change upon annealing. Li-7 T-1 is shorter (similar to 8.5 s) in sol-gel glass as prepared than in its melt-quenched counterpart (similar to 13 s) due to dipolar-dipolar Li-H interaction. Li-7 longitudinal relaxation behavior captures a part of a complex devitrification process which is driven by the loss of both residual solvent and moisture.