COMPOSITION EXHIBITING REVERSIBLE COLOR CHANGE AND EXTERIOR PARTS FOR CLOCK USING THE SAME

摘要

A composition which shows a body color change, instantaneously and reversibly, in response to change in an external light source and is excellent in various properties such as resistance to light, and exterior parts for a clock using such a composition. The above-mentioned composition exhibiting reversible color change comprises fine particles of at least one type of rare earth element oxides represented by the general formula: M2O3, wherein M represents Ho, Nd or Pr, and a light-transmittable base having the particles dispersed therein. By using the composition, a color change layer is disposed on a dial plate and the like, which is one of exterior parts of a clock.