Title

Polyhedral Arrangements in Lanthanum Aluminoborate Glasses

Abstract

We have used magic-angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy to examine the polyhedral arrangements in ternary lanthanum aluminoborate glasses. We have characterized two glass-forming series: xAl 2O 3·(1-x)LaB 3O 6 and 0.25La 2O 3·yAl 2O 3·(1-y)-B 2O 3. 11B MAS NMR reveals a decrease in the fraction of four-coordinated boron atoms with increases in the Al 2O 3 content in both series. 27Al MAS NMR has detected four-, five- and six-coordinated aluminum atoms in complex aluminoborate networks similar to those reported elsewhere for alkaline-earth aluminoborate glasses. Raman spectroscopy reveals a variety of borate and aluminoborate moieties, including isolated groups as well as methaborate chains and rings. These results indicate that the La 3+ ion acts as a modifier to the aluminoborate network.

Department(s)

Materials Science and Engineering

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1997 American Chemical Society (ACS), All rights reserved.

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