Effect of SrO and TeO2 on the physical and spectral properties of strontium tellurite boro-titanate glasses doped with Cu2+ ions.

• Increasing the SrO concentration affects the number of Cu2+ ions (spins). • Optical absorption studies confirm the existence of Cu2+ions. • SHP values endorse the site symmetry around Cu2+ ions is tetragonally distorted (D 4h) octahedral site. • The bond parameters of STTBC glasses are mostly ionic. • The incorporation of modifier oxide SrO in place of TeO 2 increase in BO 4 population. A new glass series of strontium tellurite boro-titanate glasses doped with Cu2+ ions were prepared with the composition (30-x)SrO-xTeO 2 –10TiO 2 –59B 2 O 3 –1CuO [STTBC] (where x = 5,4,3,2&1 mol%) using the melt quenching technique. The effect of varying the mol% of SrO and TeO 2 on the physical and spectroscopic properties were investigated. XRD, SEM, EDS, UV–VIS, EPR and FTIR analysis were carried out to observe changes in the STTBC glass structure. From the optical absorption data the cut-off wave length, the optical band gap, Urbach energy values, etc., were calculated. The electron paramagnetic resonance (EPR) spectra (experimental & theoretical) of these glasses were extensively studied by deriving the spin-Hamiltonian parameters, bonding coefficients, paramagnetic susceptibility and crystal-field parameters etc. The higher order perturbation approach is employed to study the interaction between the ligand and the central Cu2+ ion. [ABSTRACT FROM AUTHOR]