Reversible generation and dissolution of 3 nm silver particles in a glass containing only silver ions are repeatedly achieved through a combination of x-ray radiation and heat treatment. X-ray irradiation and 400 degreesC heat treatment induce a yellow color, whereas heating at 500 degreesC can change the glass to colorless again. X-ray irradiation produces large amounts of silver atoms and defects, mainly nonbridging oxygen hole centers (NBOs), in glass. Heating at 400 degreesC accelerates the aggregation of silver atoms into forming silver particles. The NBOs can continuously oxidize the silver atoms of particles into silver ions at higher temperature, leading to dissolution of the silver particles. (C) 2001 American Institute of Physics.