Nonlinear optical response of C 10 PPV solution was investigated by using the resonant femtosecond optical Kerr effect (OKE) method. The experimental results revealed that the OKE signal showed an ultrafast rising followed by a fast and a slow relaxation process with time constant of 200 fs and 400 ps, respectively. By analysing the photoluminescence spectra of C 10 PPV and C 10 PPV doped with C 60 , it is suggested that the 400 ps slow component can be assigned to the singlet exciton migration among different conjugated segments inside polymer.