Application of Photochromism to Fluid Measurements

Fundamental Properties of Photochromic Dyes of Spiropirans

Abstract

In this research, fundamental experiments for application of photochromism to fluid measurements and flow visualization are carried out. For use of photochromism in fluid measurements and flow visualization, it is necessary that the most suitable density of dye and power of the laser are selected. The excimer laser beam (wave length=308 nm) is used to form a dye trace. The dye is dissolved in ethanol. Length and thickness of the dye trace, depending on the concentration of dye (0.04-0.00075 weight %), are measured by a CCD camera. It is found that the length of the dye trace is longer for low concentration of dye than for high concentration. The approximated distributions of thickness of the dye trace enables to predict the length of the trace depending on the concentration of dye.