A category of new photochromatic storage material has been found suitable f
or rewritable digital video disc (DVD). The ratio of transmissivity before
and after the write-in process is 3:1 at lambda = 450 nm (blue) and 1:7 at
lambda = 650 nm (red), with a transition time of 2-3 ns. The number of writ
e-erase cycles is about 1,000.