In this research paper we are reporting synthesis, structural and optical investigations of barium strontium titanate borosilicate glasses with addition of La₂O₃. Glasses were synthesized by conventional rapid melt quench method. Infrared absorption spectra, for various (Ba,Sr)TiO₃ borosilicate glass samples having glass system 64[(Ba_1-xSr_x)TiO₃]-35[2SiO₂-B₂O₃]-5[K₂O]-1[La₂O₃] (x = 0.3, 0.5, 0.6, 0.8 and 1.0), were recorded over a continous spectral range from 450 - 4000 cm^-1. IR spectra were analyzed to determine and differentiate the various vibrational modes in the structural changes. Raman spectroscopy of all glass samples were also carried out wavenumber range form 200 - 1500 cm^-1. These two complementary spectroscopic techniques revealed that the network structure of the studied glasses is mainly based on BO₃, pentaborate groups linked to BO₄ tetrahedra and units placed in different structural groups, the BO₃ units  are dominanting. The recorded IR and Raman spectra of different glasses are used to clarify the optical properties of the prepared glass samples correlating with their structure and compositions. UV-Vis spectroscopy was carried out in range of 200 - 800 nm. The optical band gap was found between 2.023 - 3.320 eV.