Photochromic materials change their colors upon irradiation with light. The main possible application of photochromic materials has been thought as use in optical data storages, hologram materials and light modulators. There have been considerably researches and studies about photochromic compounds. There are 2 types of photochromic compounds, P-type and T-type. The photogenerated P-type compound can be converted back to its initial structure by irradiation with a specific wavelength of light. Meanwhile, the photogenerated T-type compound can be converted back to its initial structure thermally.
However, the thermal bleach reaction of photogenerated T-type compounds requires several minutes at room temperature, and for practical use in certain applications, it demands a much faster speed in the return to the initial state. Hxaarylbisimidazole (HABI) was discovered in the early 1960s by Hayashi and Maeda, and it has subsequently attracted significant interest because of its unusual physical properties. The solution of HABI changes from colorless to purple under UV irradiation. The thermal transformation of TPIRs to HABI requires several minutes at room temperature.
Kanto Chemical has commercialized pseudogem-Bis(diphenylimidazole) [2.2] paracyclophane and pseudogem-Bis(3,3’, 4,4’ – tetramethoxydiphenylimidazole) [2.2] paracyclophane novel hexaarylbisimidazole (HABI) derivatives which have a [2.2] paracyclophane structure. This novel compounds are originally designed and synthesized by professor Abe from Aoyama Gakuin University. These compounds have an excellent color switching character. They are colorless when dissolved in benzene, and change to blue or green upon UV irradiation. After the irradiation ceases, these color bleaches immediately.
- Rapid Color-Switching
- High Fatigue Resistance
- Photochromism at a Wide Range of Temperature