A butadiene．styrene copolymer of low styrene content (5％，Wt．)has been eharac-terized by 1H NMR to have only isolated styrene units on the chain．The fluorescence spectra of the sample in dilute solutions of a good solvent (dichloroethane) at 25-—26℃ showed monomer fluorescence only．ChangeS of the fluorescence spectra from a good sollvent to poor solvents (dichloroethane-methanol mixture)．and from dilute to con-centrated solutions up to the solid film confirmed that exeimer formation exists between nonadjacent ehromophores in the chain and between interchain ehromophores． Com-parision of the spectra obtained from a dilute θ-solution and solid film gave us an estimation of the relative importance of the intrachain excimer interaction and inter-chain exeimer interaction in the solid sample studied．These results may help us to visualize the interpenetration and entanglement of polymer coils during transition from a dilute solution to a concentrated one and to a solid polymer．