Third-order nonlinear optical main chain polymer material and method for preparing the same

In a method for preparing a nonlinear optical polymer material by reacting (a) a diol compound and (b') a dicarboxylic acid compound, the improvement comprising the step of:

• using, as said diol compound (a), a .chi..sup.(3) compound having no less than 3 but no more than 7 .pi.-conjugated bonding groups and having ends each substituted with a hydroxyl group, and being represented by formula (I) below:
• ##STR19## wherein D and D', which are the same or different, each represent an electron donor;
• rings represented by ##STR20## each represent a .pi.-electron conjugated ring selected from the group consisting of a benzene ring, a thiophene ring, and a furan ring;
• Xi and Yi, which are the same or different, each represent N or CH, with --Xi.dbd.Yi-- representing a .pi.-conjugated bonding group;
• i is a positive integer of 1 to n;
• and n is a positive integer of 3 to 7,
• said .chi..sup.(3) compound and said dicarboxylic acid compound being subjected to incorporated polycondensation to form a third-order nonlinear optical main chain polymer consisting of a polyester having a .chi..sup.(3) component derived from said .chi..sup.(3) compound being incorporated in a main chain of said polyester and connected thereto through covalent bonds at both ends of said .chi..sup.(3) component so that said polymer main chain is interrupted by said .chi..sup.(3) component.

A method for synthesizing a nonlinear optical polymer material obtainable by reaction between (a) a diol compound and (b) a bifunctional compound which reacts with said diol (a) and is selected from the group consisting of a diisocyanate compound and a dicarboxylic acid compound, comprising the step of:

• using as said diol compound (a), a .chi..sup.(3) compound having no less than 3 but no more than 7 .pi.-conjugated bonding groups and having ends each substituted with a hydroxyl group, and being represented by formula (I) below:
• ##STR21## wherein D and D', which are the same or different each represents an electron donor;
• rings represented by ##STR22## each represent a .pi.-electron conjugated ring selected from the group consisting of a benzene ring, a thiophene ring, and a furan ring;
• Xi and Yi, which are the same or different, each represent N or CH, with --Xi.dbd.Yi-- representing a .pi.-conjugated bonding group;
• i is a positive integer of 1 to n;
• and n is a positive integer of 3 to 7,
• said .chi..sup.(3) compound and said bifunctional compound being subjected to polyaddition to form a third-order nonlinear optical main chain polymer selected from the group consisting of a polyurethane and a polyester, having a .chi..sup.(3) component derived from said .chi..sup.(3) compound being incorporated in a main chain of said polymer and connected thereto through covalent bonds at both ends of said .chi..sup.(3) component so that said polymer main chain is interrupted by said .chi..sup.(3) component.