Fourier transform infrared (FT-IR) spectra of xBaO-15Na(2)O-(70-x)B2O3-15SiO(2) glass system with x=0, 5, 10, 15 and 20 (mol%) has been measured in the spectral range 400-4000 cm(-1) at room temperature in order to understand the characteristic frequencies of the chemical bonds and bonding mechanisms, which are susceptible to the structural and spectral changes. The effect of gamma irradiation in the dose range 0.1 kGy-60 kGy on the infrared absorption spectra of these glasses is also reported. The change in the glass structure due to the effect of composition is also discussed. It has been observed that irradiation of the glasses with the gamma rays increases the BO3 groups and the non bridging oxygens which make the network loose. (C) 2012 Elsevier B.V. All rights reserved.