ELECTRON-SPIN-RESONANCE AND OPTICAL-ABSORPTION SPECTRA OF CU2-(30-X)NA2O-70B(2)O(3) GLASSES( IONS IN XNAI)

Electron spin resonance (ESR) and optical absorption spectra of xNaI-( 30 - x)Na2O-70B(2)O(3) glasses containing 1 mol% CuO have been investi gated at room temperature. The optical absorption spectra of all the g lass samples exhibited a broad asymmetric absorption band which corres pond to the d-d transitions bands due to Cu2+ ions. From the ESR spect ra the spin-Hamiltonian parameters were evaluated. It was observed tha t the ground state of Cu2+ is d(x2-y2) orbital and the site symmetry a round Cu2+ ions is tetragonally distorted octahedral. The bonding co-e fficients were evaluated using the optical and ESR data to obtain info rmation about Cu2+-ligand bond nature. The basicity of sigma-type symm etry was independent of the glass composition while the pi-type basici ty was found to vary as a function of the glass composition.