The physical and structural properties of Cr3+ doped 19.9 ZnO + xLi2O + (30 x) Na2O + 50B2O3
(5 6 x 6 25) (ZLNB) glasses have been studied. Powder X-ray diffraction patterns indicated the amorphous
nature of the glass samples. The physical parameters of all the glasses were also evaluated with
respect to the composition. They exhibit the non-linearity providing the evidence for mixed alkali ions
effect. The infrared spectra of the glasses in the range 400–4000 cm1 showed the presence of BO3 and
BO4 local structures in all the glass systems. No boroxol ring formation was observed in the structure
of these glasses. Optical absorption and electron paramagnetic resonance studies were carried out at
room temperature. From the optical absorption data various optical parameters such as optical band
gap, Urbach energy were evaluated. Crystal field and Racah parameters are evaluated from optical
absorption spectra. The EPR spectra of Cr3+ doped ZLNB glasses exhibited resonance signals at
g = 4.066 and g = 1.9779 characteristic of Cr3+ ions. The evaluated bonding parameters suggest the covalent
nature.