Un-doped and cobalt oxide (CoO) doped lithium borate glasses with different concentrations (0.1, 0.3, and 0.5 mol %) were prepared by the conventional melting process at an approximate temperature of 1100 °C. The X-ray diffraction analysis showed the amorphous structure of the prepared glasses. Fourier transform infrared (FTIR) spectra of the synthesized glasses proved a gradual change in the glass network due to the transformation of the trigonal BO3 units into the tetrahedral BO4 units with the formation of non-bridging oxygens with the increase of CoO concentration and irradiation dose to 60 kGy. Minor changes occurred in the vibration bands of the FTIR spectra of lithium borate glasses with the increase of CoO concentration, where a slight lowering and broadening in the already existed peaks for BO3 and BO4 can be observed indicating the well dissolved of CoO in the glass matrix. The optical absorption spectra of the glasses before and after electron beam irradiation with different doses have been studied and the optical band gap, Urbach energy and refractive index also have been obtained. The results showed broad and strong absorption peaks in the visible range; these peaks can be attributed to the presence of the cobalt ions in the octahedral and tetrahedral configurations with different valence states. It is observed that the prepared glasses have a high sensitivity to electron beam irradiation which makes these glasses applicable to be used as dosimeters especially with low doses.