Photostimulated Spiropyran for Instantaneous Visualization of Thermal Field Distribution and Flow Pattern.

The study of thermocapillary convection has attracted the attention of researchers due to the importance in both fundamental and industrial aspects. To trace the state of flows in real time during thermocapillary convection, the development of imaging methods and tools is essential. Here we use a benzothiazole unit-bearing spiropyran (BS1-SP) as a photostimulated indicator to visualize the details of instantaneous temperature distribution and flow pattern on the surface of volatile solvent simultaneously with a high spatial and temporal resolution during convection. This work provides insights into dynamic self-organization and thermo-hydrodynamics taking place in evaporating systems, and a useful tool to study these behaviors.