Phthalocyanine Doping Of Sio <sub> 2 </ Sub> Properties Of The Spectral Characteristics Of The Gel Glass And The Nonlinear Optical Limiting

Metallophthalocyanines (MPc) exhibit, among many useful properties, the ability to protect sensors against short, intense optical pulses deleterious to efficient sensor operation. It is possible by means of low temperature sol-gel techniques to obtain porous monolithic composites encapsulating all sorts of complex organic molecules. We report here the study of four kinds of MPc ( NiTSPc, ZnTSPc, A1TSPcC1 and ArOPcPd) encapsulated in silica x-gel matrix obtained by the sQl-gel technique. These composites are transparent, stable and exhibit interesting optical properties. Absorption in the visible region of the UV/Vis spectrum reveals aggregation of MPc species to form dimers that modit~ the optical absorption of excited states and the resulting optical limiting properties. We investigate the relative importance of the structure of MPc molecules and changes of physicochemieal parameters during the sol-gel process affecting dimerization in order to control and inhibit dimerization. The experiments performed show that while all MPc species strongly tend to dimerization as the sol-gel time goes on, both the introduction of axial legand and ring substitution on the MPc molecules and the addition of CEL as dispersant can effectively suppress dimerization. The nanosecond optical limiting characteristics of the four kinds of MPc doped Si02 x-gel matrix are measured at 532nm with IOns pulses. The results show that ArOPcPd doped composite has the strongest optical limiting effect because of its central heavy metal atom and the high concentration of monomers existing in the composite.