article published yes Sara Sandlass author Friedrich J Stricker author 7aca2cfc-46cf-11f0-abd3-8c96b5186745 Daniel Fragoso author Javier Read de Alaniz author Michael J. Gordon author Molecular photoswitches provide a means for imparting synthetic structures with intrinsically logical and highly tunable photoresponsive properties. One variety of organic photoswitches known as Donor-Acceptor Stenhouse Adducts, or DASAs, are promising candidates for next generation light responsive materials because of their unique ability to stabilize three photochemically distinct isomeric states in solution, while their counterparts are strictly limited to binary state behavior. In this work, we show how polymethacrylate host matrices shift the energetic landscape of DASA relative to solution, prohibiting accumulation of an intermediate third isomeric state by decelerating critical steps in the photoswitching mechanism. Specifically, we employ a dual-wavelength, phase locked detection scheme to probe thermal isomerizations in the switching process that occur at fast (~ms) time scales that are inaccessible by standard UV–Vis spectroscopic techniques. The results of this study provide valuable insight into the mechanism of multistate DASA reactivity and establish the foundation necessary to guide future efforts in offsetting kinetic matrix effects to enable dynamic, three state photoswitching in polymeric hosts. Elsevier2023 eng 1010-6030 1873-266610.1016/j.jphotochem.2023.114964 444 yes Sandlass, S., Stricker, F. J., Fragoso, D., de Alaniz, J. R., &#38; Gordon, M. J. (2023). Effect of polymer host matrix on multi-stage isomerization kinetics of DASA photochromes. <i>Journal of Photochemistry and Photobiology A: Chemistry</i>. Elsevier. <a href="https://doi.org/10.1016/j.jphotochem.2023.114964">https://doi.org/10.1016/j.jphotochem.2023.114964</a> Sandlass, Sara, Friedrich J Stricker, Daniel Fragoso, Javier Read de Alaniz, and Michael J. Gordon. “Effect of Polymer Host Matrix on Multi-Stage Isomerization Kinetics of DASA Photochromes.” <i>Journal of Photochemistry and Photobiology A: Chemistry</i>. Elsevier, 2023. <a href="https://doi.org/10.1016/j.jphotochem.2023.114964">https://doi.org/10.1016/j.jphotochem.2023.114964</a>. Sandlass, Sara, et al. “Effect of Polymer Host Matrix on Multi-Stage Isomerization Kinetics of DASA Photochromes.” <i>Journal of Photochemistry and Photobiology A: Chemistry</i>, vol. 444, 114964, Elsevier, 2023, doi:<a href="https://doi.org/10.1016/j.jphotochem.2023.114964">10.1016/j.jphotochem.2023.114964</a>. S. Sandlass, F.J. Stricker, D. Fragoso, J.R. de Alaniz, M.J. Gordon, Journal of Photochemistry and Photobiology A: Chemistry 444 (2023). Sandlass S, Stricker FJ, Fragoso D, de Alaniz JR, Gordon MJ. Effect of polymer host matrix on multi-stage isomerization kinetics of DASA photochromes. <i>Journal of Photochemistry and Photobiology A: Chemistry</i>. 2023;444. doi:<a href="https://doi.org/10.1016/j.jphotochem.2023.114964">10.1016/j.jphotochem.2023.114964</a> S. Sandlass, F. J. Stricker, D. Fragoso, J. R. de Alaniz, and M. J. Gordon, “Effect of polymer host matrix on multi-stage isomerization kinetics of DASA photochromes,” <i>Journal of Photochemistry and Photobiology A: Chemistry</i>, vol. 444. Elsevier, 2023. Sandlass S, Stricker FJ, Fragoso D, de Alaniz JR, Gordon MJ. 2023. Effect of polymer host matrix on multi-stage isomerization kinetics of DASA photochromes. Journal of Photochemistry and Photobiology A: Chemistry. 444, 114964. 218212026-05-06T10:57:28Z2026-05-18T09:19:40Z