Chinese scientists may soon invent an electricity-free light after developing a new kind of "persistence" glass with a memory.

The new glass will be used widely when the technique is mature, Su Keng of the Chinese Academy of Sciences said recently in Changchun, the capital of China's northeastern province of Jilin.

Because of its memory function, a thumb-sized chip of the glass can contain an encyclopedia and dynamic three-dimensional images for long periods, Su said.

The glass is treated with a special kind of red persistence material, Su explained. Cover it with paper containing words or images, expose it to radiation such as ultraviolet rays or X-rays, and the glass can "memorize" the words and images.

It will release the stored information in a dark environment if illuminated by long-wave light like sunshine, Su said.

Persistence materials usually give out weak light for an hour or two.

But scientists at the Changchun Institute of Applied Chemistry under the CAS have experimented with rare earth as the active element in persistence materials, and they have developed materials that can emit green, blue, purple or red light for many hours.

( April 22, 2002)