Crosslinkable Main-Chain Second-Order Nonlinear Optical Polyimide for Electro-Optic Applications

Polymeric materials are superior to inorganic and organic crystals for second-order nonlinear optical (NLO) applications because of their low dielectric constant, large nonlinearity, light weight and ease of process-ability. These features have led to tremendous interest in the development of polymeric NLO materials for practical uses. The specific goal of this research is to develop second-order NLO polymers for electro-optic devices. This proposal focuses on design, synthesis and fabrication of NLO polymers with large second order optical nonlinearity, low optical loss, and long term stability of the NLO properties at elevated temperatures. A new series of crosslinkable polimides containing tolane-based NLO chromophores is proposed. The Tg and molecular weight of the soluble polimides can be controlled by adding proper amounts of end capping agent. The chain end hydroxyl groups provide the opportunity for the polimide to form cross-lined networks by using an NLO active alkoxysilane dye as a crosslinking agent. This system combines high Tg and crosslinked network characteristics to enchance the temporal stability. Preliminary results in our laboratory indicate the expected stability in a poled\crosslinked polyimide sample. The detailed characterization of structure, property and the linear and NLO properties will be carried out.