2ND-HARMONIC GENERATION FROM TRINITRO-SUBSTITUTED SUBPHTHALOCYANINES FILMS - EVIDENCE OF NONCENTROSYMMETRIC MOLECULAR-ORGANIZATION

Second-harmonic generation from lambda = 1.06 mu m fundamental light h as been measured in both evaporated and spin-coated films of trinitro- substituted subphthalocyanines. Ordering of these noncentrosymmetric m olecules with the dipole moment perpendicular to the film face has bee n achieved either by the deposition process (evaporated samples) or by corona poling (spin-coated samples). The second-order susceptibilitie s chi(31)((2)) = 2.36 X 10(-9) esu (for vacuum evaporated samples) and chi(31)((2)) = 9.62 X 10(-10)-1.14 X 10(-9) esu (for poled spin-coate d samples) have been determined by comparison with an X-cut LiNbO3 cry stal used as reference. (C) 1997 American Institute of Physics.