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Phosphate glasses modified with transition metals

Authors: Koudelka Ladislav | Mošner Petr | Kalenda Petr

Year: 2020

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Phosphate glasses modified with transition metals	Our studies of ternary phosphate glasses were devoted mainly to three transition metal oxides MoO3, WO3 and Nb2O5, which are able to form in various ternary systems large glass transition regions. Structure of glasses in the BaO-MoO3–P2O5 ternary system was studied by Raman and 31P NMR spectroscopies. The glass-forming region in the ternary system was determined, and stable glasses with 0-70 mol% MoO3 were obtained. From the NMR and Raman spectra of glasses, a structural model was proposed. Structural network contains mostly MoO6 octahedra and PO4 tetrahedra. In glasses with a high MoO3 content Raman spectra showed on the formation of clusters composed of MoO6 units. MoO6 octahedra prevailed in the glass structure, similarly to crystalline MoO3 and to the compound Ba(MoO2)2(PO4)2. Formation of MoO4 tetrahedra was proposed in the glasses with a low P2O5 content. Phosphate glasses of the ternary system BaO-Nb2O5-P2O5 were studied in two compositional series with a constant BaO or Nb2O5 content. Chemical durability of the Nb2O5-containing glasses is high and the glass transition temperature increases significantly with increasing Nb2O5 content as well as the index of refraction. At low Nb2O5 content niobium forms isolated octahedra NbO6 incorporated in the glass network, but when Nb2O5 content increases, these octahedra are linked into chains and further into three-dimensional clusters.	Phosphate; glasses; Raman spectra; transition metals; glass structure