TRANSFERRING RESEARCH TO TEACHING - THE CASE OF PHOTOCHROMISM

Photochromism is the reversible transformation of a chemical specie between two forms by the absorption of light (photoisomerization), where the two forms have different absorption spectra. It can be considered as a fast growing domain of research as a five-fold increase of the number of publications has been observed since 1990s. Anyone, even without being familiar with photochromic process can easily understand the concept of reversible change and be interested in color changes. Furthermore, several photochromic systems (T and P-type) appear as useful tools to illustrate many chemical concepts from high school to postgraduate level up to mainstream audience. Indeed, we demonstrate that commercially available T-type compounds such as 6-NO2 BIPS (spiropyran, Figure 1) or T1259 (spirooxazine) can be used to developed cheap, non-toxic and sustainable experiments based on the kinetics of the back reaction (discoloration reaction): 1. to investigate kinetics (rate constant, order, activation constant) and thermodynamics parameters for undergraduate classroom or laboratory experiment from both absorption (UV-Visible [1] and IR [2]) and fluorescence measurement [3]; 2.to illustrate kinetics factors in high school courses when dissolved in acetone or ethyl acetate as an all-in-one system [4]; 3. to discuss the effect of the environment (solvent [5], polymer matrix [6], nanoparticles [7], acido-basicity [8]) for postgraduate laboratory works, 4. to design easy to handle devices when dispersed in a polymer matrix (PPMA, varnish, polystyrene) for popular science demonstrations and 5. to create art structures [9]. [1]Piard, J; Guibert, C; Dabard, C; Demurget, N Hitier, M; Mahieu, N Mele, L. BUP. 2018, 112 (1002), 471–504 [2]Piard, J; Clède, S, BUP. 2023, Submitted. [3]Piard, J; Sowa, J, BUP. 2020, 114 (1024), 501–517. [4]Piard, J; Guibert, C; Dabard, C; Demurget, N Hitier, M; Mahieu, N Mele, L. BUP. 2018, 112 (1003) 667–682 [5]Piard, J, JCE. 2014, 91 (12), 2105–2111 [6]Piard, J; Sowa, J; Batatia, I, BUP. 2020, 114 (1028), 1019–1033 [7]Piard, J; Sowa, J; Batatia, I, BUP. 2020, 114 (1029), 1107–1120. [8]Piard, J; Castanet, J; Attia J, Clavier G, BUP. 2023, Accepted [9]https://www.youtube.com/watch?v=nMTfE8rYB9g