Spectral investigations on VO2+ ion doped in CaO–SrO–Na2O–B2O3 glass systems

Glasses of the (20 − x)CaO–xSrO–(20 − y)Na2O–60B2O3 − y (CSNB) system with (5 ≤ x ≤ 15) mol% and y = 0.1 mol% of V2O5 were characterized by X-ray diffraction (XRD), EPR (Electron Paramagnetic Resonance), Optical absorption Spectra and FT-IR (Fourier transform Infrared Spectroscopy) studies. EPR spectra of all the glass samples exhibit resonance signals characterstic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in CSNB glasses were present in octahedral sites with tetragonal compression and belong to C4v symmetry. Spin-Hamiltonian parameters ‘g’ and ‘A’ were evaluated. The Optical band energy (Eopt) and Urbach energy (ΔE) were calculated from their ultra violet edges. By correlating EPR and Optical data the molecular orbital coefficients have been evaluated. IR spectra of these glasses were analyzed in order to identify the contribution of each component to the local structure that determines the physical properties of these glasses.

► Correlated EPR and Optical absorption studies on VO2+ ions doped CSNB glasses. ► VO2+ ions doped CSNB glasses were found to be tetragonally compressed octahedral site symmetry. ► The spin-Hamiltonian parameters g and A were found to be independent of V2O5 content. ► The low values of k indicate the poor contribution of the Vanadium 4 S orbital to the Vanadyl band. ► The FTIR studies show that the structural units such as BO3, BO4 and VO4 are in disorder manner.