On the reasons of reduction in the absorptive capacity of associating molecules of pigments

The paper is concerned with the concentration reduction in the absorptive capacity of a number of molecules of pigments. It is shown that this process is not always associated with the formation of their colorless forms. Study of the temperature behavior of concentrated pigment solutions, as well as of their luminescense spectra points to the fact that the reason for reduction in the absorptive capacity is frequently the association of the molecules of the solute. Here partial decoloration of pigment solutions with increase in its concentration is a rather widespread process and manifests itself in the association not only of uniform, but also of nonuniform molecules of pigments.