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Time‐resolved fluorescence depolarization has been used to measure electronic excitation transport among naphthyl chromophores in polymeric glasses. 2‐ethylnaphthalene randomly distributed in PMMA and 2‐vinylnaphthalene/methyl methacrylate copolymer in PMMA were studied. It was found that excitation transport is dispersive at all temperatures studied, from 50 K to room temperature, i.e., the extent of transfer depends on the excitation wavelength within the S0–S1 absorption band. A theory based on the nondispersive, Forster mechanism for excitation transfer has been developed to describe dispersive transport. Good agreement between the theoretical and experimental results are achieved without resorting to adjustable parameters. Both the theory and experiment show that, for the observable used here, excitation at a certain wavelength, called the ‘‘magic wavelength,’’ results in a time dependence that is identical to the Forster nondispersive result, i.e., dispersive transport appears to vanish.

The transport of electronic excitations among chromophores which are randomly tagged or end tagged on finite flexible polymer chains in the amorphous solid state is described. First, the previously reported first order cumulant expansion treatment of excitation transport among chromophores randomly distributed in solution is extended to treat finite volume systems with nonrandom chromophore distributions. The method is demonstrated by considering chromophores randomly distributed in a finite sphere. The results are in good agreement with a previous treatment of this problem using a density expansion. The probability of finding the initially excited chromophore, still excited at time t, Gs(t), is calculated. Gs(t) is directly related to fluorescence depolarization and other observables. Gs(t) is then calculated for a finite flexible polymer chain in a polymer blend which is randomly tagged in low concentration with chromophores. The method permits any form of the polymer pair correlation function to be use...