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XRD, TEM, IR, Raman and NMR Spectroscopy of In Situ Crystallization of Lithium Disilicate GlassThe structure of a Li2O-2SiO2 (LS2) glass was investigated as a function of pressure and temperature up to 6 GPa and 750 C respectively, using XRD, TEM, IR, Raman and NMR spectroscopy. Glass densified at 6 GPa has an average Si-O-Si bond angle approx.7deg lower than that found in glass processed at 4.5 GPa. At 4.5 GPa, lithium disilicate crystallizes from the glass, while at 6 GPa a new high pressure form of lithium metasilicate crystallizes. The new phase, while having lithium metasilicate crystal symmetry, contains at least 4 different Si sites. NMR results for 6 GPa sample indicate the presence of Q4 species with (Q(sup 4))Si-O-Si(Q(sup 4)) bond angles of approx.157deg. This is the first reported occurrence of Q(sup 4) species with such large bond angles in alumina free alkali silicate glass. No five- or six- coordinated Si are found.
Document ID
20060024726
Document Type
Reprint (Version printed in journal)
Authors
Fuss, T. (Missouri Univ. Rolla, MO, United States)
Mogus-Milankovic, A. (Rudger Boskovic Inst. Zagreb, Croatia)
Ray, C. S. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Lesher, C. E. (California Univ. Davis, CA, United States)
Youngman, R. (Corning, Inc. Corning, NY, United States)
Day, D. E. (Missouri Univ. Rolla, MO, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Nonmetallic Materials
Distribution Limits
Public
Copyright
Other