TY - JOUR

T1 - Vibrational spectroscopy analysis of the structure of 0.5xNa2O-0.5xBaO-(100-x)B2O3 glass System: from superstructural units and short-range order to the physicochemical properties prediction

AU - Барабанов, Никита Максимович

AU - Тюрнина, Наталья Геральдовна

AU - Тюрнина, Зоя Геральдовна

AU - Поволоцкий, Алексей Валерьевич

PY - 2025/8/1

Y1 - 2025/8/1

N2 - This study explores the short- and medium-range structures of borate glasses with the composition 0.5xNa2O•0.5xBaO•(100-x)B2O3 (x = 15, 20, 25, 33.3, 40 mol%) and a constant Na2O/BaO ratio equal to 1 using vibrational spectroscopy methods (IR and Raman). Based on an extensive literature analysis of crystalline borates’ spectra and quantum-chemical modeling of borate superstructural units, a set of deconvolution bands was identified in the Raman spectra of the investigated glasses. These bands were used to calculate the distribution of superstructural units as a function of the glass composition. However, the accuracy of such calculations was limited due to overlapping deconvolution bands of units with different tetrahedron counts and the absence of distinct vibrational bands of metaborate rings in the studied spectral region. Using IR spectroscopy, the N4 ratio, which reflects the fraction of tetrahedral boron, was determined alongside related to the short-range structural characteristics of the glasses. A combined technique was proposed to calculate the absolute fractions of superstructural units by integrating Raman-derived data with IR-based insights into the short-range structure. This approach yielded superstructural unit fractions closely matching the independent thermodynamic predictions for binary borate glasses. The structural data enabled calculations of key glass properties (density, molar volume, and molar refractivity), which were compared with experimental values. Both stoichiometric model, assuming that the borate network comprises units identical to binary crystalline borates, and a mixed model, incorporating ternary compounds (e.g., Na2O-2BaO-9B2O3 and Na2O-2BaO-5B2O3), were employed. The mixed model was essential for phase diagram regions with ternary crystalline compounds, while the stoichiometric model performed better outside these regions. Combination of both models resulted in average deviations from experiment of less than 0.03 g/cm3 for density and 0.3 cm3/mol for molar volume. The proposed methodology for structural and property calculations based on vibrational spectroscopy data is valuable for studying underexplored borate systems lacking sufficient thermodynamic data.

AB - This study explores the short- and medium-range structures of borate glasses with the composition 0.5xNa2O•0.5xBaO•(100-x)B2O3 (x = 15, 20, 25, 33.3, 40 mol%) and a constant Na2O/BaO ratio equal to 1 using vibrational spectroscopy methods (IR and Raman). Based on an extensive literature analysis of crystalline borates’ spectra and quantum-chemical modeling of borate superstructural units, a set of deconvolution bands was identified in the Raman spectra of the investigated glasses. These bands were used to calculate the distribution of superstructural units as a function of the glass composition. However, the accuracy of such calculations was limited due to overlapping deconvolution bands of units with different tetrahedron counts and the absence of distinct vibrational bands of metaborate rings in the studied spectral region. Using IR spectroscopy, the N4 ratio, which reflects the fraction of tetrahedral boron, was determined alongside related to the short-range structural characteristics of the glasses. A combined technique was proposed to calculate the absolute fractions of superstructural units by integrating Raman-derived data with IR-based insights into the short-range structure. This approach yielded superstructural unit fractions closely matching the independent thermodynamic predictions for binary borate glasses. The structural data enabled calculations of key glass properties (density, molar volume, and molar refractivity), which were compared with experimental values. Both stoichiometric model, assuming that the borate network comprises units identical to binary crystalline borates, and a mixed model, incorporating ternary compounds (e.g., Na2O-2BaO-9B2O3 and Na2O-2BaO-5B2O3), were employed. The mixed model was essential for phase diagram regions with ternary crystalline compounds, while the stoichiometric model performed better outside these regions. Combination of both models resulted in average deviations from experiment of less than 0.03 g/cm3 for density and 0.3 cm3/mol for molar volume. The proposed methodology for structural and property calculations based on vibrational spectroscopy data is valuable for studying underexplored borate systems lacking sufficient thermodynamic data.

KW - Borate glass

KW - DFT calculations

KW - Modifiers

KW - Short-range order

KW - Spectroscopic data

KW - Superstructural units

UR - https://www.mendeley.com/catalogue/7bb6c446-e64d-3696-9b99-fa24c0430b6f/

U2 - 10.1016/j.ceramint.2025.04.429

DO - 10.1016/j.ceramint.2025.04.429

M3 - Article

VL - 51

SP - 32451

EP - 32464

JO - Ceramics International

JF - Ceramics International

SN - 0272-8842

IS - 20-B

ER -