Improved method of corona poling for highly developed dipolar orientation

New maleimide-based high-T-g polymer with good solubility (PHND) was synthe sized for second-order non-linear optics. The PHND polymer was obtained by radical copolymerization of N-(4-hydroxyphenyl) maleimide and 2-norbornene followed by polymer modifying reactions with 4-[N-ethyl-N-(2-hydroxyethyl)a mino]-4'-nitroazobenzene (DR-1) as a dye using Mitsunobu reaction process. High quality thin film was obtained from the PHND due to a good solubility in organic solvents. The films were treated by corona poling technique. In order to achieve the highest possible dipolar orientation, an improved meth od of corona poling and an optimized condition for treating PHND film were proposed. Optical non-linearity of poled films was measured by second harmo nic generation (SHG) and electro-optic (EO) measurement. The PHND polymer p oled at the optimized condition exhibited large SHG coefficients (d(33)) mo re than 600 x 10(-9) e.s.u (250 pm/V) at the wavelength of 1.064 mum for fu ndamental Eight source. It should be noted that this value is move than twi ce as much as that obtained under conventional corona poling conditions. Us ing the poled PHND thin film with large optical non-linearity, EO device wa s fabricated and successfully achieved high performance. Copyright (C) 2000 John Wiley & Sons, Ltd.