Fig. 3. (a) Typical writing, relaxation and erasing sequence for the film of BP35-BAZ-
35CN, irradiated with the incident laser beam at 532 nm with the intensity of 200 mW/
cm2. Point A: the linearly polarized laser (writing beam) is turned on; Point B: the
writing beam is turned off; Point C: the circularly polarized laser (erasing beam) is
turned on; Point D: the writing beam is turned on again. (b) The relaxation processes
after irradiated for 5 min (curve a), 15 min (curve b), 25 min (curve c).