RECENT DEVELOPMENT IN POLYDIACETYLENE SYNTHESIS: UNCONVENTIONAL POLYDIACETYLENES FOR NLO APPLICATIONS

Unconventional methods to obtain thin films of polydiacetylenes are described. These methods include preparation of films of polydiacetylene containing polymers, the preparation of polydiacetylene microcrystals dispersed in common polymers and the polymerization of diacetylenes in the molten state. It was shown that highly transparent thin films having χ(3) values of the order of 10−9 to 10−10 esu can be obtained from these materials simply by spin coat casting followed by irradiation or thermal polymerization of the diacetilenes in the polymers, or by irradiation at temperatures above the melting points, for the diacetylenes which undergo polymerization in the molten state. The important advantage of such methods is the simplicity of their processing into thin films. There is a good possibility of increasing the χ(3) values and improving the optical quality of the film by molecular designing and by further experimentation with the preparation conditions.