Ionic complexes of bis(hydroxyarylidene)alkanones with strong polymeric bases as a new class of third-order nonlinear optical chromophores

Complex formation of various mono- and bis(hydroxyarylidene)alkanones with poly(1,10-decamethyleneacetamidine) in solution and in the solid phase was investigated by UV/vis and NMR spectroscopy. It could be shown that due to the strong basicity of the polyamidine a deprotonation of the chromophores occurred. This resulted in a significant shift of the longest wavelength ab sorption band of the chromophores to higher wavelengths. Additionally, thir d-order nonlinear optical activity was evidenced on solution cast films. Be sides the optical properties, the thermal behavior of the mixtures was also influenced by the interactions between the polymer and chromophore. An inc rease of the glass transition temperature of the polymer of about 60 K was attributed to an ionic network formation. The complexes showed good film-fo rming properties and sufficiently high thermal stability.