Study on the synthesis and optical properties of polyurethane-imide

Abstract

In this paper, Polyurethane-imide (PUI) which has the advantages of polyurethane and polyimide is synthesized and introduced to apply in the slab optical waveguide devices. The PUI is characterized by infrared spectrum (FT-IR), differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Slab optical waveguide is prepared via spin coating the cyclopentanone solution of PUI on top of K9 glass and cured at 140 °C for 20 minutes to complete removal of the solvent from the film. The film-formability of PUI is characterized by atomic force microscope (AFM). The results of DSC and TGA indicate that the PUI exhibits high thermal stability up to its glass-transition temperature (Tg) of 206 °C and 10% heat loss temperature of 310°C. Optical properties of absorption behavior and propagation loss are investigated in slab waveguides, and propagation loss of 1.782 dB/cm at 1310nm in TE (transverse electric field) mode has been achieved by using prism-coupler method. The results show that polyurethane-imide has distinct merits: good processability, high thermal stability and moderate glass-transition temperature, excellent film-formability, and low propagation loss. These advantages of polyurethane-imides make them suitable as electro-optic polymeric materials in integrated optics.