4 Stepwise Two-Photon Photochromism
67
Fig. 4.6 a Transient absorption spectra and b dynamics of bisTPIC in benzene at different excitation intensity of the 355-nm nanosecond laser pulse. c Time evolution of the time-resolved FT-IR
spectra of bisTPIC in CD 2 Cl 2 after irradiation of intense laser pulse (4.0 mJ/pulse) [36]
Table 4.1 Half-lives of the transient species of PIC and bisPIC derivatives in benzene at 298 K
PIC
p-bisPIC (μs)
m-bisPIC (μs)
bisTPIC
BR
0.25 μs
0.40
0.65
3.2 ms
Q
–
8.0
3.6
0.99 s
much shorter than those of bisImD, the stepwise two-photon photochromism of
bisTPIC can be induced by CW light sources. Therefore, these fast stepwise twophoton photochromic reactions are promising for practical fast-responsive nonlinear
photoresponsive materials with the reduced power threshold.
67
Fig. 4.6 a Transient absorption spectra and b dynamics of bisTPIC in benzene at different excitation intensity of the 355-nm nanosecond laser pulse. c Time evolution of the time-resolved FT-IR
spectra of bisTPIC in CD 2 Cl 2 after irradiation of intense laser pulse (4.0 mJ/pulse) [36]
Table 4.1 Half-lives of the transient species of PIC and bisPIC derivatives in benzene at 298 K
PIC
p-bisPIC (μs)
m-bisPIC (μs)
bisTPIC
BR
0.25 μs
0.40
0.65
3.2 ms
Q
–
8.0
3.6
0.99 s
much shorter than those of bisImD, the stepwise two-photon photochromism of
bisTPIC can be induced by CW light sources. Therefore, these fast stepwise twophoton photochromic reactions are promising for practical fast-responsive nonlinear
photoresponsive materials with the reduced power threshold.