Incorporation of highly efficient second- third-order nonlinear optical chromophores into poly(amido-amine) backbones

We report here on the synthesis of new polymers carrying chromophores active for second- and third-order nonlinear optical (NLO) applications. Some of these systems show exceptionally large NLO molecular properties such as high first hyperpolarizabilities and high two-photon-pumped frequency-upconversion lasing efficiencies. Different types of polymeric and copolymeric backbones have been investigated in order to tune the properties of the bulk material and optimize its efficiency. Factors such as the linking reaction approach, chromophore number density, cross-linking ratio, and thermal properties can be controlled and tuned depending on the application. In particular, we have found that NLO molecular components carrying a primary amino group attached to the chromophore by means of a short aliphatic chain can act as comonomers in poly(amido-amine) synthesis, a family of synthetic polymers in which amido and tertiary amino groups are regularly arranged along the main backbone. Linear and soluble or, alternatively, highly crosslinked poly(amido-amine) networks can be easily obtained with high loading (5-40% by weight) of the chromophore. In addition, hydroxylated chromophores can be covalently linked to properly functionalized acrylic polymers, such as poly(2-methacryloxyethyl)imidazolylformate.