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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