Using infrared cameras, one is able to get a thermal signal from evaporating liquid layers or droplets. Also the evolution of drying fruits has been monitored. The equipment used to this end can be found here: Camera|InfraRed
When a thin film of liquid is evaporating, regular hexagonal convection cells are visible with an infrared camera. As the film becomes thinner and thinner, the liquid becomes stable again and these cells vanish. This critical height was measured and compared favorably with theories taking into account the effect of evaporation. More information can be found at http://bit.ly/2ayNX6d .
An evaporating droplet as seen with the infrared camera. Marangoni convection cells can be seen near the droplet edges.