SPECTROSCOPIC STUDY OF CHLOROPHYLL a IN ORGANIC SOLVENTS AND POLYMERIZED ANHYDROUS POLYVINYL MATRIX

In this paper we present a spectroscopic study of chlorophyll a in solutions and in anhydrous polyvinyl alcohol films. Absorption, excitation and emission spectra, combined with fluorescence lifetime and time-resolved anisotropy measurements show that chlorophyll a in anhydrous polyvinyl alcohol films exists in a purely monomeric state. Furthermore, it appears that the monomeric chlorophyll a exhibits an efficient excitation energy transfer in this polyvinyl alcohol matrix. These results are rationalized in terms of a model in which the chlorophyll a molecules are located within pockets, formed by the polymer chains. It is concluded that the chlorophyll a-anhydrous polyvinyl alcohol film is a suitable system for studying energy transfer processes, especially because the factors governing energy transfer such as mutual orientation and separation of the molecules can easily be controlled.