Infrared recording with thermochromic cu(2)hgl(4)

Reflectance vs temperature measurements on thermochromic Cu(2)HgI(4) show phase transition hysteresis, which forms the basis for recording applications. Long term reflectance relaxation at room temperature has been noted, together with the ability to invert reflectance from the high temperature phase to the low temperature phase by further addition of energy. Specific heat measurements also show the phase transition hysteresis. Image recording sensitivity measurements indicate that 27 mJ/cm(2) are needed to switch a particular Cu(2)HgI(4) paint sample at its transition. Spatial resolution is shown to be at least as good as 4 microm.