Dynamics of macromolecular chains. III. Time‐dependent fluorescence polarization studies of local motions of polystyrene in solution

Fluorescence anisotropy decay experiments are described for polystyrene in various ethylacetate‐tripropionin mixtures. Decay curve trends agree with the proposed theoretical autocorrelation function. Study of the effects of viscosity shows that the mean relaxation time varies according to a nonlinear law for low viscosities and that the relaxation time θ, reflecting the effects of the possible departures from the motions permitted by an ideal tetrahedral lattice, obeys a law of the type: θ = α + b η. Furthermore, the effects of the direction of the fluorophore transition moment are examined.