Photochromic amorphous molecular materials

Shirota, Y, Moriwaki, K., Yoshikawa, S., Ujike, T., and Nakano, H. 4- [di(biphenyl-4-yl)amino]azobenzene and 4,4 -bisfbis(4 -rerr-butylbiphenyl-4-yl amino]azobenzene as a novel family of photochromic amorphous molecular materials. /. Mater. Chem. 8, 2579, 1998. 

Utsumi, H., Nagahama, D., Nakano, H., and Shirota, Y. A novel family of photochromic amorphous molecular materials based on dithienylethene. J. Mater. Chem. 10, 2436, 2000. 

Nakano H, Takahashi T, Kadota T, Shirota Y. 2002. Formation of the surface relief grating using a novel azobenzene based photochromic amorphous molecular material. Adv Mater 14 1157 1160. 

Tanino T, Yoshikawa S, Ujike T, Nagahama D, Moriwaki K, Takahashi T, Kotani Y, Nakano H, Shirota Y. 2007. Creation of azobenzene based photochromic amorphous molecular materials synthesis, glass forming properties, and photochromic response. J Mater Chem 17 4953 4963. 

Nakano, H. Takahashi, T. Kadota, T. Shirota, Y. (2002). Formation of Surface Relief Grating Using a Novel Azobenzene-based Photochromic Amorphous Molecular Material. Ado. Mater., 2002,14,1157-1160. 

Shirota, Y. Moriwaki, K Yoshikawa, S. Ujike, T. Nakano, H. (1998). 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. J. Mater. Chem., 1998,8,2579-2581.. 

Synthesis, Properties, and Applications of Photochromic Amorphous Molecular Materials and Electrochromic Polymers... 

The synthesis, properties, and implications of photochromic amorphous molecular materials and novel organic electrochromic materials including molecular gels and polymers containing pendant oligothi[Pg.173]

Two novel classes of photochromic amorphous molecular materials based on azobenzene and dithioiylediene have been created. Photochromic behavior of these materials in solution and as amorphous films has beoi elucidated. These photochromic amorphous molecular materials based on azobenzene and didiienyledirae have found implications for SRG fcnmation and dual image formation, respectively. 

In order to obtain stable amorphous states of organic materials, the glass transition temperature (Tg) of the materials should be higher than room temperature. Molecular motion is frozen at temperatures below Tg, and crystal growth is suppressed. The Tg of la was found to be lower than room temperature. Although several photochromic amorphous materials containing azobenzene unit have been synthesized, the practical use of amorphous azobenzenes is limited because of thermal instability of the cis-isomer and low reactivity in the solid state. Figure 17.3 shows some molecular structures... 

---