Influence of chromium ions on photonic applicability of Na2O-Bi2O3-B2O3-SiO2 glass system

Glasses, with composition 10Na2O–10Bi2O3–20B2O3–(60-x)SiO2: Cr2O3 (0 x 0.25), synthesized by melt quenching procedure were characterized by XRD and conducted optical absorption, EPR, and FTIR spectroscopic techniques. The optical absorption spectra portrayed a strong absorption peak at about 642 nm owing to 4A T (F) with a couple of envelopes at about 681 and 712 nm due to 4A T and 4A E transitions, respectively. All doped samples showed two EPR signals, each at low and high magnetic fields caused by the chromium ion isolation and interchange interactions of Cr3＋-Cr3＋ ions, respectively. FTIR spectra have revealed the behaviour of various structural units for different concentration of Cr2O3 in the glass matrix. With the assistance of spectroscopic studies, the observed fall in the rigidity of the samples with higher concentrations of Cr2O3 is attributed to presence of high concentrations of octahedrally resided Cr3＋ ions, which gain more suitability for lasing action.