Nonconjugated conductive polymers have a ratio of double bonds to total bonds of less than ½ are used to produce compositions with unexpected non-linear optical characteristics in this invention. Large third order optical effects including quadratic electro-optic effect and two-photon absorption have been measured in nonconjugated conductive polymers after doping the polymers. Among the nonconjugated polymers are styrene-butadiene-rubber copolymer (SBR), poly(β-pinene), poly(ethylene-pyrrolediyl) derivative, polynorbornene, cis-1,4 polyisoprene and trans-1,4 polyisoprene. The enhancement of the non-linear optical effect is due to the special charge-transfer complex structure and formation of nano-optical domains. Among the doping materials are electron acceptors such as iodine and antimony pentachloride.