Mixed Alkali Effect in Mn2+ Doped XLi2O+(50-X) K2O+50B2O3 (10?X?30) Glasses

G. Srinivasa Rao, P. Narayana Murthy, R. V. S. S. N. Ravikumar

Abstract: Divalent Mn2+ containing xLi2O + (50-x) K2O + 50B2O3 (10?x?30) (LKB glasses) mol% glasses are prepared by using melt quench technique. Various physical parameters are evaluated from measured values of density and refractive index for observation of mixed alkali effect. Structural changes of Mn2+ doped LKB glasses are investigated by optical absorption, electron paramagnetic resonance and FT-IR spectroscopic studies. The EPR spectra of Mn2+ doped LKB glasses exhibited a characteristic hyperfine sextet around g = 2.02. The optical band gap and Urbach energies are calculated which confirmed the mixed alkali effect. FT-IR measurements of all glasses revealed that the network structure of glass system is mainly based on BO3 and BO4 units placed in different structural groups.

Keywords: Alkali borate glasses, Mixed alkali effect, Melt quench technique, Electron paramagnetic resonance