We have investigated the dynamics of photoexcitations in chiral assemblies of textitp-phenylenevinylene oligomers functionalized with hydrogen-bonding motifs. In the regime of low excitation densities, the luminescence transients are influenced by the migration of excitons to defect sites, indicative of fast diffusivity of excitons along the molecular assemblies. In addition, at high excitation densities, bimolecular exciton annihilation is shown to result in the fast depopulation of the stacks' excitonic energy levels.