"..SpectraDisc, a spin-off from Spectra Science, a Providence, Rhode Island developer of laser technologies, is working on a special material to coat DVD discs, which start to self-destruct from the first moment of play. The coating is only around half a micron thick, around 1/200th of the thickness of a human hair. The thickness of the coating determines how long the disc lasts. The time limit can range from minutes to three days.." NULL