Gamma irradiation of cholesteric products: effect of the presence of organic solvents

The shift ΔT of the selective reflection temperature due to an exposure to γ-rays is studied for a mixture of cholesteric substances dissolved in various organic solvents. Values of ΔT such as 0.20C per krad can be obtained. The influence of the solvent nature (carbon tetrachloride, chloroform, trichloroethylene) is also discussed. It is shown that the shift ΔT is due to the presence of radiolysis products of the solvent; this effect is more specially studied in the case of carbon tetrachloride containing a radical scavenger. (author)