Sodium bismuth borate glasses with composition (100–x)(0.785B₂O₃–0.215Bi₂O₃)–xNa₂O where x=0, 2, 4, 6, and 8 mol%, were prepared by standard synthesized melt–quenching method. The amorphous and vitreous nature of these samples was confirmed by X–ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis. The density of the samples was measured using Archimedes principle and the molar volumes were determined from the density data. The spectroscopic properties of glass samples were studied using Fourier Transform Infrared Spectrometer (FTIR) and Raman spectroscopic techniques. The density of the samples was found to vary non–linearly with the Na₂O content, however, a slight variation of the glass transition temperature was observed. The addition of Na₂O in 78.5B₂O₃–21.5Bi₂O₃ glass causes changes in the features of the FTIR and Raman spectra. Both types of IR and Raman spectroscopic revealed that the network structure of the studied glasses is mainly based on BO₃ and BO₄ units, and bismuth exists as BiO₃ pyramidal and BiO₆ octahedral units.