Physical and structural study of Al2O3–NaBr–B2O3–CuO glasses

Glasses of composition Al2O3–NaBr–B2O3 doped with copper ions prepared using melt quenching method. The effect of sodium bromide on alumino-borate glasses is investigated using various physical and spectroscopic methods. The increase in NaBr content decreased the density values of the samples nonlinearly which is attributed to replacement of relatively higher ionic radii of bromide ions (1.96 Å) in the place of lower ionic radii of oxygen ions (1.4 Å). At optical wavelengths, optical properties of the samples like band gap, Urbach energy, refractive index, etc., were evaluated and explained. Spin-Hamiltonian parameters (SHP) (gII, g⊥, AII and A⊥) were calculated from EPR spectra. The SHP values suggested the Cu2+ ion is in the ligand field surrounded by tetragonally contorted in octahedral locations with dx2-y2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${d}_{{x}^{2}-{y}^{2}}$$\end{document} as lowest energy state. The bonding coefficient (α2,β2andβ12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha^{2} ,\beta^{{2}} \,{\text{and}}\,\beta_{1}^{2}$$\end{document}) values were also determined using broad absorption band in UV–visible spectra and EPR. A deconvoluted spectrum is used to get exact band positions in the FTIR spectra. Residual graph is drawn to know the percentage difference in experimental and simulated curves. FTIR spectra confirmed that the structure of the glass is build up of AlO3, AlO4, BO3 and BO4 units.