Fig. 1. Schematic representation of different photoswitch environments using a spiropyran derivative as an example.

a A spiropyran derivative (orange propellor) in (left) solution, (middle) a solvent-filled rigid solid matrix, and (right) a solid solvent-free porous matrix mimicking behavior in the gas phase (a gas-phase analog). b A plot demonstrating the drastic change in photoisomerization rate constants as a function of the photoswitch type and its environment. The exact values for photoisomerization rate constants are provided in Table 1.