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Structural Role of Aluminum Oxide in Ternary Aluminum Sodium Borate Glass System
E. Mannaa, A.M. Abdelghany, M.I. Abdelghany and G. El-Damrawi

Glasses in the ternary system 𝑥Al₂O₃ – (30 – 𝑥) Na₂O-70B₂O₃, where 𝑥 varies between zero and 21 mol% were successfully prepared by the annealing method. Density, molar volume, and their derivatives were measured and calculated to illustrate the intermediate role of Al₂O₃ in the host sodium borate structure. X-ray diffraction pattern (XRD) of the studied glasses approved the amorphous nature of the all-prepared composition. Fourier transforms infrared FTIR spectral data revealed the presence of both triangular and tetrahedral boron groups with variable fractions. FTIR Deconvolution analysis technique (DAT) has been used to follow the variation of the fraction of tetrahedrally coordinated boron (N₄) upon substitution of Na₂O with Al₂O₃. Decreasing N₄ upon exchange of Na₂O with Al₂O₃ confirms that a portion from Al₂O₃ entered the glass as tetrahedral species (AlO₄) which plays the role of glass former. Raman spectral data reveal the presence of trigonal (BO₃) and tetrahedral (BO₄) structural groups correlated with the presence of borate partner while most Al³⁺ ions enter the glass as tetrahedral species (AlO₄), which play the role of glass former

Keywords: Aluminum sodium borate glass; FTIR; DAT; Raman spectra