PHOTOFADING BEHAVIOR OF TRIAZINYLAMINOSTILBENE FLUORESCENT BRIGHTENERIN CELLOPHANE

The photofading behavior of CI Fluorescent Brightener 85 (FB 85) is in vestigated on cellophane. The initial photofading reaction of FB 85 on cellophane is trans-cis isomerization, and the subsequent reaction is assumed to be photodegradation. The initial photofading rate of FB 85 on cellophane is accelerated by brightener concentration and atmosphe ric moisture, whereas the addition of sodium carbonate to the dyebath retards photofading. A kinetic analysis suggests the participation of a bimolecular reaction in addition to photoisomerization through a mon omolecular reaction. The contribution of the bimolecular reaction incr eases as the moisture content increases. Added salt reduces the contri bution of the bimolecular reaction in photofading of FB 85 on cellopha ne.