Photolysis of Optical Whiteners in the Presence of Haloarenes

Halobenzenes and sodium salts of halobenzenesulfonic acids decelerate photochemical degradation of optical whiteners in aqueous 2-propanol or in a polyvinyl alcohol matrix owing to T-T transfer of the electronic excitation energy from the substrate to the additive and also to the quenching effect of the heavy atom of the additive. In all the cases, the efficiency of deceleration of luminophore photodegradation grows in going from chloro to bromo and then iodo derivatives.