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 sol utions and in anhydrous polyvinyl alcohol films. Absorption, excitatio n and emission spectra, combined with fluorescence lifetime and time-r esolved anisotropy measurements show that chlorophyll a in anhydrous p olyvinyl alcohol films exists in a purely monomeric state. Furthermore , it appears that the monomeric chlorophyll a exhibits an efficient ex citation energy transfer in this polyvinyl alcohol matrix. These resul ts are rationalized in terms of a model in which the chlorophyll a mol ecules 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 b ecause the factors governing energy transfer such as mutual orientatio n and separation of the molecules can easily be controlled.