Organic polymers are attractive nonlinear materials because of their both large nonlinear coefficient and ultrafast response time. By use of the modified nonlinear Schrodinger equation, we have investigated numerically the effect of delayed nonlinear response time, as well as second and third order dispersion, on the propagation of femtosecond optical pulse. It has been shown that the red shift due to delayed nonlinear response time in frequency domain increases with the increasing of delayed nonlinear response time exceeds a certain value.