Optical memory and multistep luminescence thermochromism in single crystals of [K.sub.2]Na[[Ag[(CN).sub.2]].sub.3]

The single crystal layered compound [K.sub.2]Na[[Ag[(CN).sub.2]].sub.3] is observed to show remarkable luminescence changes involving optical memory and luminescence thermochromic changes. The unprecedented occurrence of both novel phenomena in the compound is found to be related to reversible photophysical changes instead of irreversible photochemical changes.