Thermodynamic model and Raman spectra of BaO-B2O3 glasses

Abstract The structure of xBaO•(1-x)B2O3 (x = 0.20, 0.25, 0.30, 0.35, and 0.40) glasses were studied by Raman spectroscopy and the thermodynamic model of Shakhmatkin and Vedishcheva (SVTDM). Nine system components were considered in the SVTDM: BaO, B2O3, 2BaO•5B2O3, 2BaO•B2O3, 3BaO•B2O3, 4BaO•B2O3, BaO•B2O3, BaO•2B2O3, and BaO•4B2O3. In all components of the SVTDM with non-negligible equilibrium abundance, only three short range order structural units were identified on the basis of structural data: trigonal boron with three bridging oxygen atoms (T3), trigonal boron with two bridging oxygen atoms (T2), and tetragonal boron with four bridging oxygen atoms (Q4). The Multivariate Curve Analysis (MCR) of the baseline subtracted and thermally corrected experimental Raman spectra was performed for three components. MCR resulted in the Raman spectra (so called loadings) and relative abundances (so called scores) of each considered structural unit. On the basis of strong positive correlations between the equilibrium molar amounts of structural units and scores, the particular structural units were attributed to individual loadings. This result was confirmed by the structural analysis of the individual loadings.