Disclosed are end point indicator compositions and devices containing them, particularly useful as air freshener devices, comprise compositions containing a polar indicator dye which assumes a first color or is colorless in the presence of a room temperature volatilizable solvent which is initially present in excess and a small amount of a proton donating compound. The indicator dye assumes a second color visually distinct from the first color in the presence of the proton donating compound after the majority of the solvent escapes from the remainder of the composition. Optionally, the compositions further include color change developers and/or secondary dyes to render the change to the second color, indicating attainment of the end point, more apparent to a user.
本发明公开了端点指示剂组合物和含有它们的装置,特别是作为空气清新剂装置使用的端点指示剂组合物,包括含有极性指示剂
染料的组合物,该
染料在室温可挥发溶剂和少量质子捐赠化合物的存在下呈现第一种颜色或无色。当大部分溶剂从组合物的其余部分逸出后,指示剂
染料在质子捐赠化合物存在的情况下呈现出与第一种颜色明显不同的第二种颜色。可选地,组合物进一步包括变色
显色剂和/或辅助
染料,使用户更明显地看到第二种颜色的变化,表明达到终点。