Methacrylate polymers containing different molar contents of nonlinear optical (NLO) active molecular segments based on 2-[4-(N-methyl,N-hydroxyethyl-amino)phenylazo]-phenyl-6-nitrobenzoxazole chromophores were synthesized, and their phase behavior and second-order NLO properties were investigated. Polymers containing 6-17 mol % chromophore segments allowed the preparation of amorphous and optically clear thin films. Some mesomorphic structuration was exhibited by a polymer with 33 mol % chromophoric units. However, this feature did not prevent the possibility of investigating the NLO properties. Nonlinear resonance-enhanced d(33) coefficients were determined by second harmonic generation experiments on spin-coated, corona-poled thin films at lambda = 1064 nm. Values ranging from 40 to 60 pm/V were measured with increasing chromophore molar contents. (C) 2003 Wiley Periodicals, Inc.