4-[di(biphenyl-4-yl)amino]azobenzene and 4,4 '-bis[bis(4 '-tert-butylbiphenyl-4-yl)amino]azobenzene as a novel family of photochromic amorphous molecular materials

We have created photochromic amorphous molecular materials containing an az obenzene chromophore, 4-[di(biphenyl-4-yl)amino]azobenzene and 4,4'bis[bis( 4'-tert-butylbiphenyl-4-yl)amino]azobenzene (t-BuBBAB), which readily form amorphous glasses above room temperature and exhibit photochromism in their ;amorphous films. We have shown that the photogenerated cis-form in the amo rphous him can be stabilized at ambient temperature by the incorporation of a bulky group; the backward cis-->trans thermal isomerization can be contr olled by temperature for t-BuBBAB.