Application of Photochromism to Fluid Measurements

本研究对光致变色技术在流体测量和流动显示中的应用进行了基础性实验。得到了以下结果：(1)光致变色染料的吸光度，研究了5种螺环吡喃类光致变色染料的吸光度随照射光波长的变化规律。光致变色染料溶解在乙醇中。结果表明，1，3，3-三甲基吲哚-6‘-硝基苯并吡喃在紫外区的吸光度比其他染料大得多。因此，这种染料非常适合于流体测量和流动显示。(2)染料痕迹的长度和密度对于光致变色在流体测量和流动显示中的应用，必须选择最合适的染料浓度和激光功率。用准分子激光(XeCl，波长=308 nm)形成染料痕迹。染料溶解在乙醇中。染料痕迹的长度和厚度取决于染料的密度(0.04%-0.00075重量%)，由ccd相机测量。结果表明，低浓度的染料比高浓度的染料有更长的痕迹长度。提出了适用于流体测量和流动显示的最佳染料密度条件。

In this research, fundamental experiments for application of photochromism to fluid measurements and flow visualization are carried out. Following results are obtained.(1) Absorbance of photochromic dyes; Absorbance, which depends on wave length of irradiated light, of 5 photochromic dyes of spiropyrans is investigated. The photochromic dyes are dissolved in ethanol. It is found that 1, 3, 3-trimethylindolino-6'-nitrobenzopyrylospiran has much larger absorbance in the ultra violet region than the other dyes. Therefore, this dye is very suitable for fluid measurements and flow visualization.(2) Length and density of dye trace 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 (operated by XeCl, 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 density 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 density of dye than for high density. The optimum condition of density of dye is proposed for fluid measurements and flow visualization.