Synthesis and electro-optic properties of novel X-type polyester containing dioxynitrobenzylidenecyanoacetate with highly enhanced thermal stability of dipole alignment

Abstract

Novel X-type polyester 5 containing 5-nitro-2,4-dioxybenzylidenecyanoacetate groups as nonlinear optical (NLO) chromophores, which constitute parts of the polymer backbone, was prepared and characterized. Polyester 5 is soluble in common organic solvents such as N,N-dimethylformamide and acetone. Polymer 5 shows a thermal stability up to 280°C from thermogravimetric analysis with glass-transition temperature obtained from differential scanning calorimetry of near 116°C. The second harmonic generation (SHG) coefficient (d 33 ) of poled polymer film at the 1064 nm fundamental wavelength is 1.78 pm V -1 . The dipole alignment exhibits a thermal stability even at 4°C higher than glass-transition temperature (T g ), and no significant SHG decay is observed below 120°C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.

Nonlinear Optical Pigments. Two-Photon Absorption in Crosslinked Conjugated Polymers and Prospects for Remote Nonlinear Optical Thermometry

“…At the same time, large optical nonlinearities are accompanied by temporal responses that can be as low as in the femtosecond range [3], raising hopes for applications in optical signal processing, e.g., in all-optical switching [4][5][6]. On the synthetic side, a considerable body of information has been accumulated about how to maximize NLO response of organic compounds and led to the determination of molecular design principles for organic [7][8][9][10] and organometallic NLO chromophores [11][12][13][14]. These principles are now commonplace tools that assist the design of new small-molecular and polymeric compounds for nonlinear optics.…”