Advances in macromolecules, perspectives and applications.Chapter 2: Macromolecular systems with second order nonlinear optical properties.

Polymers for applications in second order nonlinear optics (NLO) have been an hot topic in applied macromolecular research since the middle of 1980s. In this Chapter, starting from the basic physical aspects of molecular NLO activity, the principal classes of NLO active molecules are described and the different ways in which the NLO active fragments can be incorporated within a polymers are examinated with emphasis on the chemical features allowing optimization of NLO performances of the final materials