The influence of singlet oxygen in the fading of carbonless copy paper primary dyes on clays

Singlet oxygen was shown to be involved in the mechanism of fading on a cla y surface of a series Of the triphenylmethane (TPM) dyes used in commercial carbonless copying paper; The dyes adsorbed on clays were found to be sing let oxygen sensitisers and the singlet oxygen produced reacted with the dye s themselves. The rate of fading of a particular dye depended upon the stru cture of the dyes, fluorans degrading faster than phthalides. (C) 2001 Else vier Science Ltd. All rights reserved.