The molar extinction coefficient, maximum absorption wavelength, reaction rate constants of trans-cis photochemical isomerization, thermal back-isomerization and photochemical back-isomerization and equilibrium constant of photochemical back-isomerization reaction of a novel photochromic liquid crystalline dendrimer G1 of the first generation containing nitroazophenyl groups on its periphery and small molecular azophenyl moiety M1 in solution were described. Photochromic rate constant of G1 in CHCl₃ and THF was 10^－1 s^－1, but that of photochromic liquid crystalline polysiloxanes containing azophenyl moieties was 10^－8 s^－1, thus the photoresponsitive rate of liquid crystalline dedrimer G1 is 10⁷ times larger than that of the latter. The equilibrium constants k_t/k_c of photochemical back-isomerization reaction of G1 are 1.76～1.77 approaching to 1, and thus it is appliable to photoswitch material.

Key words: photochromic liquid crystalline dendrimer, photoisomerization, photo back-isomerization, thermal back-isomerization, photoswitch material, photoelectrical informational storage material