Figure 2.

Determination of rate constants and maximum MC to SP conversion in relation to the total photon emission rate: The rate constants of spiropyran-DO3A-Gd, dissolved in water and ethanol were determined after illumination with the blue LED using equation (2). The insert displays the data points between 0 s⁻¹ and 10 × 10¹³ s⁻¹. A linear regression analysis was performed which gave R² = 0.99156 for spiropyran-DO3A dissolved in water and R² = 0.98982 for spiropyran-DO3A dissolved in ethanol. For spiropyran-DO3A-Gd dissolved in water the regression analysis gave R² = 0.99978 and R² = 0.97866 for spiropyran-DO3A-Gd dissolved in EtOH.