OPTIMAS. Teilprojekt: Entwicklung von Pseudo-Ladder-Polymeren mit hohen X"("3")-Werten Abschlussbericht

As one partner of the OPTIMAS research cooperation network, we have tried to develop stable pseudo-ladder oligomers and polymers with high third-order optical nonlinearities on the basis of appropriate chromophores for applications of the techniques of optical switching and measuring. Novel dimers and trimers of (un)symmetrical cyanines and a homologous series of new oligomeric indolyl squaraines (dimer to pentamer) could be prepared on the basis of new concepts and characterized. The oligomeric cyanines and squaraines are thermally stable and possess third-order nonlinear properties that are larger than those of the corresponding monomers and were measured by the Bayreuth group. Oligomers and polymers of (hetero)aromatics were investigated, as to whether their planarization by hydrogen-bonds (forming of pseudo-ladder systems) increases the effective lengths of conjugation and therefore the third-order nonlinearities. Some of the planned systems for investigation were available. The rigidization by hydrogen bonds in a homologous series of 1,2,3-oxadiazole/hydroquinone oligomers results in a remarkable increase of the 3rd polarizabilities. During the project two concepts were developed on the basis of the relationships between the structure and the 3rd polarizability: rigidized merocyanines at the cyanine limit and oligoenes with induced charge alternation. The former possess comparably large 3rd polarizabilities to the corresponding cyanines and are thermally very stable. The NLO data of the polarized oligomers and polymers indicate that the concept may be realized. (orig.)SIGLEAvailable from TIB Hannover: F00B88 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman