3RD HARMONIC-GENERATION SPECTRA OF DEGENERATE GROUND-STATE POLY(DIPROPARGYL) AMINES

We report third harmonic generation (THG) studies on solution-cast thi n films of two poly(dipropargyl) amines, poly(N-hexyl dipropargylamine ) (PDPHA) and a salt derivative, poly(dipropargyl-N-hexyl-N-methylammo nium triflate) (PDPHMAT), covering pump energies from 0.6 to 1.4 eV. T he THG data show the simultaneous two- and three-photon resonance expe cted for degenerate ground state conjugated polymers at 0.68 eV for PD PHA and 0.73 eV for PDPHMAT. The peak values of the third-order suscep tibility are 1.0 x 10(-10) esu for PDPHA and 2.9 x 10(-11) esu for PDP HMAT; off-resonance values are nearly an order of magnitude smaller.