Degradation of a stilbene dye (SOTGL) in aqueous solutions under gamma-radiation

The effect of radiation on the colour intensity of aerated, oxygen and nitrogen-saturated aqueous solution of Solophenyl Orange TGL was investigated. Experiments show that the absorption band decreases gradually with the increase of the dose in all cases and the destruction of the skeleton of the dye molecule is promoted, by the presence of oxygen. The radiochemical degradation yield (Gd) was calculated and was found to decrease experimentally with the increase of dose for low concentrations. The influence of pH on the degradation of the dye was studied. The specific bimolecular rate constant of the reaction of SOTGL with the hydroxyl radical was determined, and was found to be 1.055 · 109M-1s-1. Suggestions are made for possible low radiation dosimetry (about 1.5 kGy) by means of spectrophotometric analysis of the absorption spectra. (author) 13 refs.; 10 figs.; 1 tab