Influence of Tungsten ions on the physical and spectroscopic properties of Na2O–PbO–Bi2O3–SiO2 glass system

The melt-quenching technique is used to synthesize the glasses under investigation. Their XRD spectra confirmed the amorphous nature. These samples are analyzed spectrally using optical absorption, EPR, and FTIR. The rise of intensity of the seen peaks in the optical absorption spectra, as well as the resonance signal in the EPR spectra of tungsten-doped samples, indicated the increasing order of W5+ ions at the expense of W6+ ions to the growing concentration of WO3. These W5+ ions occupy an octahedral position and act as modifiers, causing structural disorders leading to depolymerization of titled glass network. The FTIR spectra of these samples exhibited vibrational bands due to various structural units present in them. The decline in the optical band gap and rise of degree of disorder in the glass matrix result in a diminution in the rigidity of the glass system, which enhances the semiconducting character with a rise in the WO3 concentration. Numerous spectroscopic investigations have revealed that glasses doped with 5 mol% of WO3 are more likely to exhibit photochromism because of their greater W5+ ion contents.