TEMPERATURE EFFECTS ON STRUCTURE AND DYNAMICS IN BORATE AND BOROSILICATE LIQUIDS - HIGH-RESOLUTION AND HIGH-TEMPERATURE NMR RESULTS

Citation
Jf. Stebbins et Se. Ellsworth, TEMPERATURE EFFECTS ON STRUCTURE AND DYNAMICS IN BORATE AND BOROSILICATE LIQUIDS - HIGH-RESOLUTION AND HIGH-TEMPERATURE NMR RESULTS, Journal of the American Ceramic Society, 79(9), 1996, pp. 2247-2256
Citations number
57
Categorie Soggetti
Material Science, Ceramics
ISSN journal
00027820
Volume
79
Issue
9
Year of publication
1996
Pages
2247 - 2256
Database
ISI
SICI code
0002-7820(1996)79:9<2247:TEOSAD>2.0.ZU;2-0
Abstract
The fictive temperature dependence of the relative abundances of three - and four-coordinated boron was investigated in several sodium berate and borosilicate glasses using high-resolution B-11 nuclear magnetic resonance (NMR). In the compositions with low sodium/boron ratios, no effect was observed, but in the borosilicates, the fraction of the tet rahedral species decreased significantly as the fictive temperature in creased because of the higher content of nonbridging oxygens, In situ, high-temperature magic-angle spinning NMR demonstrated the exchange o f the two species at a rate comparable to the shear relaxation rate, i ndicating a close link between B-O bond breaking and viscous flow.