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- Structural investigations of tungsten silver phosphate glasses by solid state NMR, vibrational and X-ray absorption near edge spectroscopies
- Univ Laval
- Universidade Estadual Paulista (UNESP)
- Universidade Federal de Alfenas (UNIFAL)
- Univ Munster
- Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
- Deutsche Forschungsgemeinschaft (DFG)
- Deutscher Akademischer Austauschdienst (DAAD)
- Fond de Chemischen Industrie
- DFG: SFB 458
- Glasses were prepared in the pseudo-binary system (1 - x)AgPO(3)-xWO(3) (0 <= x <= 0.6 mol%). The structural evolution of the vitreous network was studied as a function of composition by thermal analysis, Fourier Transform Infrared spectroscopy (FTIR). Raman scattering, high resolution (31)P solid state NMR and XANES at the W-L(1) absorption edge. For compositions with x ranging from 0 to 0.5 a pronounced increase in the glass transition temperature is observed, suggesting a significant increase in the glass network connectivity. At the same time Raman spectra indicate that tungsten atoms are linked to non-bridging oxygen atoms (W-O- or W=O bonded species) whereas the (31)P MAS-NMR spectra indicate the successive formation of new P-O-W linkages. The formation of some anionic tungsten sites (if these are revealed by the presence of W-O terminal bonds) implies an increase in the average degree of polymerization of the phosphate network, which is consistent with the compositional evolution of the (31)P MAS-NMR spectra at low x values. For higher x-values. the Raman spectra indicate the presence of W-O-W linkages. W-L(1) XANES data indicate that at least 90% of tungsten atoms are octahedrally coordinated. (c) 2011 Elsevier B.V. All rights reserved.
- Journal of Non-crystalline Solids. Amsterdam: Elsevier B.V., v. 357, n. 10, p. 2126-2131, 2011.
- Elsevier B.V.
- Tungstate glasses
- Glass structure
- Solid state NMR
- Acesso restrito
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