3RD-ORDER NONLINEAR OPTICAL-PROPERTIES OF A VANADYLNAPHTHALOCYANINE DERIVATIVE

Third-order nonlinear optical susceptibility of a vanadylnaphthalocyanine (VONc) possessing terminal tetrakis-(pentoxycarbonyl) (COO-C5H11) substituents is reported for the first time. The chi(3)(-3omega; omega, omega, omega) values measured by the third harmonic generation technique between 2.1 and 1.5 mum varied with the wavelengths, increasing closer to resonance. The maximum chi(3)(-3omega; omega, omega, omega) determined for VONc(COO-C5H11)4 was 8.6 X 10(-11) esu at 2.1 mum. Though the terminal long chain (pentoxycarbonyl) groups on the naphthalocyanine ring dilute the magnitude of optical nonlinearity, the chi(3)(-3omega; omega, omega, omega) values were found to be quite large arising from the extended pi-electron conjugated system introduced by benzoisoindole units. Furthermore, the change of ring size and ligand may each affect the packing of the VONc(COO-C5H11)4 molecules and thus cause variations in the intermolecular interactions and the optical nonlinearity.