Neutron irradiation effects on optical and structural properties of silicate glasses

The affect of thermal neutron irradiation on the optical and structural properties of the quaternary silicate glasses of varying compositions has been studied. Experimental results reveal the formation of colour centers in the visible region of the optical spectra. The optical energy gap and the width of the energy tail above the mobility gap have been measured before and after irradiation. The optical energy gap has been found to decrease with increase in neutron fluence. The decrease in the energy gap with the decrease in silica content of the glass is also observed. The change in glass network structure as revealed by the formation of non-bridging silicon–oxygen (Si–O–NBO) groups has been observed and explained in terms of radiation induced structural defects and composition of the glass.