Optical and structural changes of TiO2/PVA nanocomposite induced laser Radiation

The laser irradiation effect of on the structural and optical properties of TiO2/PVA nanocomposite at different loading of TiO2 nanoparticles as (1.25%, 2.5%, 5%, 7.5%, 10% TiO2 /PVA) was investigated. Two different types of laser sources were used Nd: YAG laser (at 266 nm) and Nitrogen laser at (337 nm). The XRD, FTIR and UV-Visible are used to reveal the structural changes and the optical parameters of the composites due to the laser irradiation. Changes of the crystalinity of the composites films were observed by XRD, where the Nd: YAG laser developed a decrease in the crystalinity of all the investigated samples, while the Nitrogen laser developed an increase of the crystalinity. IR spectroscopy showed strong reduction of -OH group as a result of both lasers. It also shows an increase in the intensity of the vibration modes at 1720 cm−1 corresponding to carbonyl formation due to the effect of Nd: YAG laser irradiation only. The intensity of the C-C bond increases after Nitrogen laser irradiation indicating the increase of crystalinity of the composites films. UV-Vis spectra indicates the photothermal effect of Nitrogen laser and the photochemical effect of Nd: YAG laser. The optical constant of the all composites samples have been calculated before and after irradiation with both two types of laser sources which coincide with the results obtained from XRD and IR studies.