Structure and Raman spectra of binary barium phosphate glasses
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Structure and Raman spectra of binary barium phosphate glasses Branislav Hruška1 · Rajesh Dagupati1 · Mária Chromčíková2,3 · Aleksandra Nowicka1 · Jaroslava Michálková1 · Jacob A. Peterson1 · Marek Liška2,3 · Francisco Munoz4 Received: 7 November 2019 / Accepted: 11 January 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract The structure of xBaO·(1 − x) P2O5 (x = 0.30, 0.35, 0.40, 0.45, and 0.50) glasses was studied by Raman spectroscopy and thermodynamic model Shakhmatkin and Vedishcheva (SVTDM). The seven system components (defined as stable crystalline phases of the BaO–P2O5 binary phase diagram) were considered in the SVTDM: BaO, P 2O5, 4BaO·P2O5 (B4P), 3BaO·P2O5 (B3P), 2BaO·P2O5 (B2P), BaO·P2O5 (BP), and BaO·2 P2O5 (BP2). Only the equilibrium molar abundances of BP and BP2 were non-negligible in all studied glass compositions. Therefore, in the next step, multivariate curve analysis (MCR) of the baseline—subtracted, thermally—corrected experimental Raman spectra, was performed for two components (BP2 and BP). MCR resulted in the Raman spectra (loadings) and relative abundances (scores) of each considered component. The MCR method reproduced 98.93% of the spectral data variance. Then, the decomposition of Malfait was used. The perfect fit between the MCR loadings and the partial Raman spectra of BP2 and BP, obtained by Malfait’s decomposition, was found, confirming the validity of thermodynamic model. Keywords BaO–P2O5 · Thermodynamic model · Raman spectra · Phosphate glass · MCR
Introduction In comparison with silicate or borate glasses, phosphate glasses possess interesting functional properties, mainly the higher refractive indexes, the lower melting temperature, and thermal expansion coefficients, and high transparency in the ultraviolet range [1, 2]. On the other hand, phosphate glasses have poor chemical durability. The chemical durability and additional properties of phosphate glasses can be improved by the addition of various metal ions into the phosphate network [3, 4]. Due to this compositional variability, phosphate glasses can be used for metal sealing applications,
* Branislav Hruška [email protected] 1
FunGlass, Alexander Dubček University of Trenčín, Študentská 2, 911 50 Trenčín, Slovakia
VILA – Joined Glass Centre of the IIC SAS, TnUAD, FChPT STU, Študentská 2, 911 50 Trenčín, Slovakia
2
3
Institute of Inorganic Chemistry of Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava, Slovakia
4
Institute of Ceramics and Glass (CSIC), Kelsen 5, 28049 Madrid, Spain
photonics, radioactive waste vitrification, medical applications, etc. [5–7]. The SVTDM enables the interpretation of the relationships between the composition, structure, and properties [8–15]. The validity of the model has to be confirmed by the comparison of its results with the available structural data [13–16]. In our previous work [16–19], we showed that the statistical analysis of the compositional and temperature series of Raman spectra validated the SVTDM thermodynamic model for the N
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