Synthesis and nonlinear optical properties of a novel X-type polyester containing dicyanovinylnitroresorcinoxy groups with enhanced thermal stability of dipole alignment

摘要

A novel X-type polyester (5) containing 4-(2',2'-dicyanovinyl)-6-nitroresorcinoxy 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-dimethylf ormamide and acetone. Polyester 5 shows thermal stability up to 300 °C from thermogravimetric analysis with a glass transition temperature obtained from differential scanning calorimetry of near 108 °C. The second harmonic generation (SHG) coefficient (d_(33)) of poled polymer films at the 1064 nm fundamental wavelength is 2.99 pm V~(-1). The dipole alignment exhibits thermal stability even at 7 °C above the glass transition temperature, and no significant SHG decay is observed below 115 °C due to the partial main-chain character of the polymer structure, which is acceptable for NLO device applications.