Effect of γ-irradiation on polyvinyl alcohol films doped with some dyes and their use in dosimetric studies

Using polyvinyl alcohol (PVA), water-soluble polymer, thin films were prepared by incorporating some dyes. On subjecting these films to γ-radiation, it was found that there is a gradual change in the colour. In case of PVA film containing methyl red sudden discolouration occurs at a dose of 30 kGy, however, optical density change was not very contrasting. In case of acid red-4, there is a gradual fading of the red colour in the dose range 10-55 kGy. The PVA film (control) without dye shows development of brownish shade. These changes can be explained in terms of scission of main chain, liberation of the H and OH radicals and their interactions with the dye molecules. It is shown that these films can be used as cheap, portable and reliable plastic detectors for dosimetry.