Photo-induced non-linear optical studies on gallium alkali borate glasses doped with TiO2

Abstract

30 Li2O − (5 − x) Ga2O3 − 65 B2O3 glasses containing small concentrations of TiO2 varying from 0 to 1.0 mol% are prepared by the melt quench technique. The X-ray diffraction results showed the amorphous nature of the sample. Various physical parameters like density, molar volume, Ti4+ ion concentration, molar refraction, polarizability, polaron radius, etc., are evaluated. The differential scanning calorimetry traces of all the samples are recorded and displayed inflection points due to glass transition Tg in the temperature region 446–460 °C. Fourier transform infrared spectra, optical absorption spectra and photoluminescence spectra of all the samples are recorded at room temperature and analyzed. Optical absorption spectra of all these glasses exhibited two clearly resolved absorption due to the excitation of Ti3+ ions. At room temperature, the recorded electron paramagnetic resonance (EPR) spectrum of present glasses exhibited a resonance signal at g ~ 1.911 referred to tetragonaly compressed octahedral sites of Ti3+ ions. Laser-induced second-harmonic generation (SHG) studies are carried out for all the glasses. These results have signified that the glass doped with 0.8 mol% of TiO2 exhibited the highest intensity of SHG signal. These results are further analyzed using the other spectroscopic studies and reasons for the highest SHG efficiency of the glass GT8 are identified and reported.