Anomalous-dispersion phase-matching (ADPM) offers large enhancements in the effective hyperpolarizabilities of nonlinear optical processes such as second harmonic generation (SHG) in organic materials. The principal barrier to the practical application of this approach is the residual absorption of asymmetric organic chromophores at the second harmonic which is shown by calculation to inherently limit the efficiency of SHG. Resonance Raman experiments on a nonlinear optical (NLO) dye optimized for doubling 800 nm light indicate that the residual absorbance is probably due to vibronic levels associated with the electronic absorption. Recent work with thin films of PMMA doped with this ADPM dye showed zero dispersion at approximately 6% concentration.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.