Ion irradiation induced effects on the optical properties of polymers: a possible correlation with the energy loss profile

In the present study, the samples of CR-39 (monomer composition C₁₂H₁₈O₇) have been implanted with 100keV Ar⁺ and Kr⁺ ions to different fluencies ranging from 5x10¹⁴ to 1x10¹⁶ ions/cm². Further, these samples were subjected to UV-Visible, FTIR and Raman spectroscopic techniques to reveal the change in the optical behaviour of the samples in terms of induced structural changes in the polymer as a result of ion irradiation. The observed decrease in optical energy gap and increase in refractive index of the material under study after irradiation to Ar⁺ and Kr⁺ ions at the same energy have been tried to explain in terms of the energy loss profile along the trajectory of the respective ions. These studies are quite important towards the development of new materials with desired properties besides their fundamental importance. (paper)