Photoinduced Shape Changes of Mixed Molecular Glass Particles Containing Azobenzene-Based Photochromic Amorphous Molecular Materials Fixed in Agar Gel.

It has been found that mixed molecular glass particles exhibit photoinduced shape changes, elongating their shapes to form stringlike structures similar to single molecular glass particles of azobenzene-based photochromic amorphous molecular materials. Furthermore, interestingly, the addition of 15 mol % photochemically inert 4,4',4″-tris[3-methylphenyl(phenyl)amino]triphenylamine enhanced the phenomenon relative to single particles of 4-[bis(4-methylphenyl)amino]azobenzene. The present mixed systems allowed to elucidate the effects of Tg and of the apparent photochromic reactivity independently by changing the mixing ratio of suitable materials. It has been clearly demonstrated that increase in the apparent photochromic reactivity enhanced monotonically the photomechanical elongation of the particles. On the other hand, it has been found that increase in Tg was favorable for the present photoinduced elongation of the particle, whereas the effect of Tg became saturated at sufficiently high Tg values.