Page 178 - Photoreactive Organic Thin Films

S. CH1RAL POLYMERS WITH PHOTOAFFECTED PHASE BEHAVIOR FOR OPTICAL DATA STORAGE 157

--Q- JP

1BOO 2400 3000 3600 4200 4800 420 440 460 480 500 520 540
(A) Time, s (B) Wavelength (cut off at 10% level), nra
FIG. 5.11 (A) Evolution of the birefringence, An ind, induced by polarized light in a copolymer film
(KW07,23 |Lim) through color filters with different transmission ranges. Typical transmission curve of a
filter shown as insert; (B) The An value induced for 10 min, versus the wavelength corresponding to the
filter transmission 10%. Point numbers correspond to the curves in Figure 5.11 A.

Illumination Intensity, mW/cm~
FIG. 5.12 (A) Evolution of the birefringence, An !n(J, induced by polarized white light in a copofymer
film (KWI9,22 u.m) without filters (/) or through grey filters of different optical density (2-4); (B) the
An value induced for 10 min, versus the light intensity.

FIG. 5.13 Evolution of the induced birefringence in a dye copolymer film (KW40,3 urn) under con-
sequent irradiation with s-polarized blue-green light, UV non-polarized light, and p-polarized blue-green
light.