In this paper we report the first hyperpolarizabilities (beta) of 12,
sulfophthalein dyes. Since these dyes are ionic in nature, their secon
d-order nonlinearities were measured by the hyper-Rayleigh scattering
technique in solution. The measured beta values are large and highly s
olvent dependent. Inclusion of solvent polarity in ab initio estimates
of static second-order polarizability does not fully account for the
experimental beta values. Contributions from the dissociated forms of
the dye in different solvents seem to play an important role in enhanc
ing beta in these systems.