A study of SiO2 glass and supercooled liquid to 1950 K via high-temperature Raman spectroscopy

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doi: 10.1016/0016-7037(94)90156-2
Authors:McMillan, P. F.; Poe, B. T.; Gillet, P.; Reynard, B.
Author Affiliations:Primary:
Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ, United States
Other:
Université de Rennes, France
Laboratoire des Sciences de la Terre, France
Volume Title:Geochimica et Cosmochimica Acta
Source:Geochimica et Cosmochimica Acta, 58(17), p.3653-3664. Publisher: Pergamon, Oxford, International. ISSN: 0016-7037
Publication Date:1994
Note:In English. 95 refs.; illus.
Summary:Wire-loop heating techniques coupled with micro-Raman spectroscopy are used to investigate SiO2 glass and supercooled liquid between room T and 1950 K. The dominant low-frequency Raman band increases with frequency and with increasing T, in contrast to the direction of normal anharmonic shifts, due to a decrease in the average Si-O-Si angle with increasing T. This change is due to the anharmonicity of the Si-O-Si bending vibration below Tg (the glass transformation range) and to the configurational changes at higher T. There is an increase in the intensity of the 606 cm-1 band due to an increase in the proportion of three-membered ring 'defect' species in the glass above Tg, indicating that structural relaxation in the liquid state is achieved by SiOSi bond breaking and reforming consistent with the activation energy for viscous flow. An energetic model is proposed for viscous relaxation in SiO2. [R.K.H.]
Subjects:Crystal structure; Glasses; High temperature; Igneous rocks; Magmas; Melts; Raman spectra; Rheology; Spectra; Temperature; Thermodynamic properties; Volcanic rocks
Abstract Numbers:95M/1604
Record ID:1995054381
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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