FTIR and the electron spin resonance studies on 59B(2)O(3)-10As(2)O(3)-(30 - x)PbO-xBaO (x = 0, 7.5, 15, 22.5, 30 mol %) glasses containing 1 mol % V2O5, or MnO2 have been carried out. The ESR spectra of V4+ ion in the glass system were recorded at X-band frequencies at 300 K. The V4+ ion in the present glass system exists as VO2+ ion in octahedral coordination with tetragonal compression. The site symmetry of vanadyl is C-4v and the ground state of 3d (1) ion is d (xy) . The spin-Hamiltonian parameters (g (aEuro-), g (aSyen) and A (aEuro-)) of VO2+ ions in the present glasses have been estimated. The spectra consist of resonance lines centered at g a parts per thousand 4.3 and g a parts per thousand 2. The resonance line centered at g a parts per thousand 4.3 has been attributed to the rhombic symmetry of the Mn2+ ions. The resonance signal at g a parts per thousand 2 is attributed to the Mn2+ ions in an environment close to an octahedral symmetry. The absence of boroxol ring in the present glass system suggested that these glasses consist of randomly connected BO3 and BO4 units. The conversion of BO3 to BO4 takes place in the glasses under investigation
