Photofading Behavior of Triazinylaminostilbene Fluorescent Brightener in Cellophane

Abstract

The photofading behavior of CI Fluorescent Brightener 85 (FB 85) is investigated 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 concen tration and atmospheric moisture, whereas the addition of sodium carbonate to the dyebath retards photofading. A kinetic analysis suggests the participation of a bimo lecular reaction in addition to photoisomerization through a monomolecular reaction. The contribution of the bimolecular reaction increases as the moisture content in creases. Added salt reduces the contribution of the bimolecular reaction in photofading of FB 85 on cellophane.