Chiral Azo polyurethane(urea): Preparation, optical properties and low power consumption polymeric thermo‐optic switch

Abstract

Abstract Azo chromophore molecule (NPMBR) was synthesized by using 4‐nitroaniline, sodium nitrite and chiral reagent, R ‐α‐methyl benzylamine. Then, NPMBR was polymerized with isophorone diisocyanate and polyether polyol to obtain novel chiral azo polyurethane(urea) (PUUR). The chemical structures of NPMBR and PUUR were characterized by FTIR and UV‐Vis spectroscopy. The UV‐induced trans/cis photoisomerization and reflex‐isomerization behaviors were investigated and the results indicated that the PUUR solution could undergo photochromism after irradiated by UV light. The measurements of refractive index and thermo‐optic coefficient (d n /d T ) of PUUR were demonstrated at different wavelengths and different temperatures by ATR technique. By using CCD digital imaging devices, transmission loss of the internal waveguide was measured. The refractive index dispersions and Sellmeyer coefficients of PUUR were obtained by Sellmeyer equation. A Y‐branched switch based on thermo‐optic effect was proposed and the performance of switch was simulated. With branching angle of 0.143° and FD‐BPM method, the result showed that the power consumption of the thermo‐optic switch could be only 0.4 mW, and the response time of the switch could reach about 3 ms. It has a significant improvement in reducing the power consumption and response time compared with those of the normal Y‐branched polymer thermo‐optic switch. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011