Poly(N-vinyl-2-pyrrolidone) (PVP) has been Mended with a urethane-urea copolymer (UU); this resulting electro-optic polymer was thought to improve the linear and nonlinear optical properties. Transparent films without scattering were obtained from the mixed solutions of PVP and UU with a wide mixture ratio. The refractive indices and absorption coefficients of the films decreased with the nonlinear optical (NLO) chromophore concentration. The optical nonlinearity, which was evaluated by the d-coefficient for second harmonic generation, was enhanced by blending 10-20 w/w% PVP with UU in spite of a decrease in the NLO chromophore concentration. No noticeable lowering of the temporal stability of the nonlinearity was observed in the blended film containing 10-20 w/w% PVP. The improvement induced by the addition of a small amount of PVP could not be explained by the interaction between the NLO chromophore and PVP but between UU and PVP. The blended films containing 10-20 w/w% PVP showed an improvement in temporal stability at 100 degreesC by additional heating during corona poling. The blending of polysulfone (PSF) with UU was examined, and the blended film containing 10 w/w% PSF showed no observable change regarding the d-coefficient and its temporal stability.