Investigation on spectral features of tungsten ions in PbO–Bi2O3–As2O3 glass matrix

Abstract

Lead bismuth arsenate glasses mixed with different concentrations of WO3 (ranging from 0 to 6.0mol%) were synthesized. Differential thermal analysis (DTA), optical absorption, ESR and IR spectral studies have been carried out. The results of DTA have indicated that there is a gradual decrease in the resistance of the glass against devitrification with increase in the concentration of WO3 upto 4.0mol%.The optical absorption spectra of these glasses exhibited a relatively broad band peaking at about 880nm identified due to dxy→dx2−y2 transition of W5+ ions; this band is observed to be more intense in the spectrum of glass containing 4.0mol% of WO3. Further, two prominent kinks attributed to 3P0→1S0, 1D2 transitions of Bi3+ ions have also been located in the absorption spectra. The ESR spectra of these glasses recorded at room temperature exhibited an asymmetric signal at g⊥∼1.71 and gll∼1.61. The intensity of the signal is observed to be maximal for the spectrum of the glass W4. The quantitative analysis of optical absorption and ESR spectral studies have indicated that there is a maximum reduction of tungsten ions from W6+ state to W5+ state in the glass containing 4.0mol% of WO3. The IR spectral studies have indicated that there is a increasing degree of disorder in the glass network with increase in the concentration of WO3 upto 4.0mol%.