Incorporation of Ladder Polymer Subunits in Formal Copolymers for Third Order Nlo Applications

Ladder polymers such as POL and PTL have been regarded as promising candidates for the third-order nonlinear optical (NLO) applications due to their highly conjugated planar pi-electron framework and high thermal stability. However, their lack of processibility has generally precluded their use. Over the past three years, however, we have demonstrated that five ring ladder subunits can be incorporated in formal 1:1 copolymers, or as pendant substituents on polymer backbones such as polyvinylphenol1,2. These materials have extremely interesting χ(3) properties related both to the magnitude of response and the decay mechanism observed during the degenerate four wave mixing process. In this paper we will explore how substituent group choice in the ladder moiety can enhance both χ(3) as well as provide improved processibility.