Thermodynamic model and Raman spectra of binary barium borate glassforming melts
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Thermodynamic model and Raman spectra of binary barium borate glassforming melts Mária Chromčíková1,2 · Armenak A. Osipov3 · Leyla M. Osipova3 · Branislav Hruška4 · Jaroslava Michálková4 · Aleksandra Nowicka4 · Jacob A. Peterson4 · Marek Liška1,2 Received: 8 November 2019 / Accepted: 11 January 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract The set of 34 baseline subtracted and thermally corrected Raman spectra of BaO–B2O3 glassforming melts with the composition xgBaO–(1 − xg)B2O3 (xg = 0.20; 0.25; 0.30; 0.35; 0.40; 045; 0.50; 0.55; 0.60) measured at temperatures ranging from 600 to 1100 °C was analyzed. The thermodynamic model of Shakhmatkin and Vedishcheva was evaluated for each glass melt. Nine following system components (defined as stable crystalline phases of the BaO–B 2O3 binary phase diagram) were considered: BaO, B2O3, 2BaO·5B2O3 (Ba2B5), 2BaO·B2O3 (Ba2B), 3BaO·B2O3 (Ba3B), 4BaO·B2O3 (Ba4B), BaO·B2O3 (BaB), BaO·2B2O3 (BaB2), and BaO·4B2O3 (BaB4). The equilibrium molar amounts of system components were used for the evaluation of the molar amounts of basic structural units Tn (trigonal boron with n-bridging oxygen atoms, n = 0, 1, 2, 3) and Q4 (tetragonal boron with 4-bridging oxygen atoms). Only three structural units (Q4, T3, and T2) with the not negligible equilibrium molar amount were found. The significant correlation between equilibrium molar amounts of Q4 and T3 was found. Malfait’s decomposition was performed for the most abundant units, i.e., T3 and T2. Multivariate curve resolution analysis performed for two components resulted in the Raman spectra (so-called loadings) and relative abundances (so-called scores) of each component. The obtained loadings were in good agreement with the partial Raman spectra obtained by the Malfait’s decomposition. Keywords BaO–B2O3 · Thermodynamic model · Raman spectra · Borate glass melts
Introduction The structure and properties of barium borate glasses are intensively studied due to their electrical and optical properties and gamma ray shielding applications [1–6]. The short-range structure can be—on the level of next nearest neighbor (NNB) distance—characterized with five structural groupings [6–9]: Q4—tetrahedral boron with four bridging oxygen atoms (i.e., [BØ4]−, Ø is bridging oxygen atom), and * Mária Chromčíková [email protected] 1
VILA – Joined Glass Centre of the IIC SAS, TnUAD, FChPT STU, Študentská 2, 911 50 Trenčín, Slovakia
2
Institute of Inorganic Chemistry of Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava, Slovakia
3
Institute of Mineralogy Ural Branch RAS, Miass, Chelyabinsk Region, Russian Federation 456317
4
FunGlass, Alexander Dubček University of Trenčín, Študentská 2, 911 50 Trenčín, Slovakia
Tn (n = 3, 2, 1, 0)—trigonal boron with n-bridging oxygen atoms (i.e., BØ3, BØ2O−, BØO22−, and BO3− 3 ). In the present paper, the high-temperature Raman spectra and structure of binary barium borate glassforming melts are studied with composition ranging from 20 to 60 mol% of BaO. According to the r
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