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Title: Glass-forming ability of TeO{sub 2} and temperature induced changes on the structure of the glassy, supercooled, and molten states

Polarized (VV) and depolarized (VH) Raman spectra are obtained for glassy, supercooled, and molten TeO{sub 2} at temperatures up to 1000 K in order to elucidate the temperature evolution of the pertinent structural and vibrational properties. The intrinsic tendency of the system for crystallization is avoided by means of a newly applied protocol, thereby enabling the recording of Raman spectra of pure TeO{sub 2} on going from the molten to the supercooled liquid and to the room temperature glass states. Following an appropriate fitting procedure, the revealed bands are assigned to specific modes of structural polymorphs. A weak polarised band at ∼880 cm{sup −1} is assigned to Te=O terminal stretching in agreement with the literature ab initio molecular orbital calculations. Subtle changes to the relative band intensities within the 550-900 cm{sup −1} stretching region are caused by temperature increase. The network-like structure of the glass/melt is composed by TeO{sub 4} trigonal bipyramid and TeO{sub 3} trigonal pyramid units. With increasing temperature, TeO{sub 4} units convert to TeO{sub 3} units with a concurrent increase in the number of Te=O sites resulting from cleavages within the network structure. The fraction of such terminal oxygen atoms has been directly estimated from the spectroscopicmore » data. The relative populations of the basic building blocks and the average number of O atoms around Te have been estimated for a wide temperature range directly from the Raman spectra, implying a gradual transformation of TeO{sub 4/2} to TeO{sub 2/2}(= O) trigonal pyramid units. The results are discussed in the context of the current phenomenological and theoretical status of the field.« less
Authors:
 [1] ;  [2] ; ;  [3] ;  [2]
  1. Department of Chemistry, University of Ioannina, GR-45110 Ioannina (Greece)
  2. (FORTH-ICE/HT), Foundation for Research and Technology Hellas, P.O. Box 1414, GR-26504 Patras (Greece)
  3. Department of Chemical Engineering, University of Patras, P.O. Box 1414, GR-26504 Patras (Greece)
Publication Date:
OSTI Identifier:
22415679
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOMS; CERAMIC MELTERS; CRYSTALLIZATION; GLASS; LIQUIDS; MOLECULAR ORBITAL METHOD; OXYGEN; PHASE TRANSFORMATIONS; RAMAN SPECTRA; TELLURIUM OXIDES; TEMPERATURE DEPENDENCE; TRANSFORMATIONS