| abstract |
A linear addition polymer having sidegroups which may be coupled to it or not through a spacer and have a molecular hyperpolarizability β of at least 10⁻³⁸ m⁴/V, characterized in that the recurring units of the polymer correspond to the formulan wherein X represents a hydrogen atom or a lower alkyl group and m = 1 or optionally 0, where n nwhen m = 1 n nY represents an group and R has the meaning of nn a) a hyperpolarizable group having a molecular hyperpolarizability β of at least 10⁻³⁸ m⁴/V, in the presence or not of a spacer, and optionally along with b) a mesogenic group in the presence or not of a spacer, and/or c) a hydrogen atom or a substituted or unsubstituted organic group having not more than 30 carbon atoms, and when m = 0 n nY represents a -CN, a substituted or unsubstituted phenyl group or a group of the formula -OR₁ or -CH₂OR₁, wherein R₁ has the meaning of a hydrogen atom or a substituted or unsubstituted aliphatic group having not more than 20 carbon atoms, nprovided that n- at least 10% of the recurring units in the polymer contain a hyperpolarizable group having a molecular hyperpolarizability β of at least 10⁻³⁸ m⁴/V, n - at the most 40% of the recurring units in the polymer contain a mesogenic group, and n- that the quotient of the degree of substitution of the recurring units with a group having a molecular hyperpolarizability β of at least 10⁻³⁸ m⁴/V and the average molecular weight of R with the meaning given under b and c amounts to at least 5 × 10⁻⁴, a non-linear optical medium thereof oriented in an electric field and electro-optical laminates comprising such a non-linear optical medium. |