Activation Energies of Light Fading of Dyes in Polymers

Abstract

Activation energies of fading of three different dye-fiber systems have been measured by fading at different temperatures: (i) three acid dyes on gelatin film, (the behavior of wool is expected to be similar to that for gelatin); (ii) four reactive dyes on Cellophane film; and (iii) three reactive dyes on nylon film. Activation energies of fading range between about 3 and 18 kcal/mole and depend on the nature of the substrate and the class of the dye. Activation energy values are found to decrease with loosening of the structure of the fiber, e.g. wool, which gives low values. Fading of wool seems to be almost insensitive to wide variations in humidity. Activation energy values of disperse dyes on nylon and disperse reactive dyes (Procinyl) on the same substrate are about the same, which tends to show that the reactive type of dye-fiber bond is not effective in lightfastness.