We have investigated the molecular reorientation dynamics of perylene incorporated into the nonpolar acyl chain region of 100 nm diameter phosphocholine unilamellar vesicles. When perylene is excited to the S-1 electronic manifold, it exhibits a different fluorescence anisotropy decay than when it is excited to its S-1 electronic manifold. In addition to differences in the polarization of the two transitions, there is a difference in the amount of excitation energy dissipated nonradiatively, because for both excitation conditions radiative emission is from the S-1 state. The data reveal a faster rotational diffusion constant for excitation to the S-2 manifold, and we interpret this finding in the context of local heating of the chromophore immediate environment by the nonradiative dissipation of energy associated with rapid relaxation from the S-2 to S-1 manifolds. Our results are consistent with transient heating on the order of 4 K, with the actual temperature increase depending subtly on whether the phospholipid acyl chains are in the gel phase or the fluid phase.