ELECTRON-PARAMAGNETIC-RESONANCE STUDY OF THE VANADYL ION IN XCOO.(1-X)(ZNO.2B(2)O(3)) GLASSES

Glasses with the composition xCoO.(1-x)(ZnO.2B(2)O(3)) have been prepa red in the CoO concentration range 0 less than or equal to x less than or equal to 0.24 containing 2 mol% V2O5. Electron paramagnetic resona nce (EPR) spectra of VO2+ of these glasses have been measured at the X -band frequency nu approximate to 9.14 GHz, at room temperature and al liquid-nitrogen temperature. Spin-Hamiltonian parameters of the VO2ions have been calculated. It is found that for x less than or equal t o 0.15 the octahedral symmetry of the V4+ site is improved. Parts of t hese glasses were annealed at 373 and 573 K for 2 h and EPR spectra we re recorded and analysed. Theoretical optical basicity values of the s amples were calculated and ii was found that the predictions made by t hese calculated values are in agreement with the experimental findings .