Pentaazadentate macrocyclic metal complexes are a kind of novel nonlinear optical materials with great potential applications in the photonics. The photofading kinetics of the complexes has been studied in different solvents by different visible radiations with different optical intensities. The results indicate that the photofading processes obey the zero-order kinetics for the reactant concentrations, which are affected only by the optical intensities and show a characterization of photochemical process. The photofading rate constants are in the range of 1.2×10^-7(in benzene)～2.0 ×10^- 5h^-1(in methanol) at visible wavelength≥500nm, and shorter visible wavelength may enhance the photofading rate constants. Electron- accepting groups, metal ions with large size and strong polar solvents can accelerate the photofading. However, the pentaazadentate metal complexes studied still exhibit higher photostability.

Key words: DISCOLORATION, PHOTOCHEMISTRY, NON LINEAR OPTICS, METAL COMPLEX, MACROCYCLIC COMPOUNDS, DYNAMICS, LIGHT STABILITY