Thermochromics are temperature sensitive inks, developed in the 1970s, that temporarily change color with exposure to temperature. They come in two forms, liquid crystals and leucodyes . Liquid crystals are used in mood rings. Leucodyes are easier to work with and allow for a greater range of applications. These applications include: forehead thermometers, battery testers , and the indicator on bottles of maple syrup that change color when the syrup is warm.

See also

• Electrochromics