Photochemistry in polymer solids—10. Photoisomerization of 1,1′-azonaphthalene in a polycarbonate film

✍ Scribed by Takuya Naito; Kazuyuki Horie; Itaru Mita

• Book ID: 103076943
• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 424 KB
• Volume: 26
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(90)90142-q

✦ Synopsis

The trans-to-cis photoisomerization and cis-to-trans thermal isomerization of l,l'-azonaphthalene (AZN) molecularly dispersed in polycarbonate (PC) films were studied in the wide temperature range from liquid helium temperature to 340 K. The rate of the photoisomerization in PC film is equal to its rate in solution up to 84% conversion, beyond which it deviates from first-order kinetics. These deviations became more marked and the final conversions decreased with decreasing temperature. These results suggest that the reactivity of AZN is controlled not only by the average mobility of the reactants but also by the heterogeneity of the reaction sites in polymer solids because of the distribution of local free-volume. The results with the deviation from the first-order kinetics were compared with two kinds of kinetic models, i.e. stretched exponential and free-volume fluctuation models. The free-volume fluctuation model is supposed to describe the characteristics of photoisomerization of AZN in PC film.