Study of mixed heavy metal fluoride bismuth borate glasses for optical applications

To investigate the structural, optical and spectroscopic properties for possible applications in optical and shielding materials, the glasses with compositional formula x CdF 2 –(25− x )PbF 2 –25Bi 2 O 3 –49.8B 2 O 3 –0.2Cr 2 O 3 ( x varies from 5 to 25 mol%) were developed by adopting melt quenching process. XRD graphs depict the glasses to be amorphous in nature. Optical and spectroscopic properties of the samples have been analyzed using optical absorption, EPR, FTIR and Raman spectra. From the optical absorption spectra, the optical band gap, the Urbach energy, Rachah parameters are evaluated. The increasing trend in the refractive index value with CdF 2 content reflects the applications in fibre optic communication. The ‘ g ’ values obtained from EPR spectrum are found to be ≈ 1.93 and ≈ 4.23 for the resonance signals. Presence of metal cations (Cd 2+ , Pb 2+ ), BiO 3 , BO 3 and BO 4 are identified from the FTIR spectra. The information about hidden peaks are obtained from the deconvoluted Raman spectra and the transfer of [BO 4 ] units to [BO 3 ] units with increase in concentration of CdF 2 is identified. Increase of CdF 2 reflected significant changes in all parameters such as density, energy band gap and refractive index. These variations make the present composition suitable for communication and in other optical fields.