How does rw dvd work

Christine Baker. Lifewire Technology Review Board Member. Christine Baker is a marketing consultant with experience working for a variety of clients. Her expertise includes social media, web development, and graphic design. Article reviewed on Apr 10, Tweet Share Email. Was this page helpful? Thanks for letting us know! Email Address Sign up There was an error. Please try again. You're in! Thanks for signing up.

There was an error. Tell us why! More from Lifewire. The 6 Best External Optical Drives of The laser darkens spots on the recording layer dye layer to record information. Rewritable media use a phase change recording layer where the write laser changes the polarization of the recording layer usually a metallic material by crystallizing it. In order to erase this layer so new data can be added, an erase laser usually the recording laser refocused to be wider then that needed to record data is used.

This erasing function heats the layer causing it to become amorphous again as it was in the blank state. Share this comparison:. If you read this far, you should follow us:. Diffen LLC, n. The key is a layer of phase-change material, an alloy composed of silver, indium, antimony and tellurium.

Unlike most solids, this alloy can exist in either of two solid states: crystalline with atoms closely packed in a rigid and organized array or amorphous with atoms in random positions. The amorphous state reflects less light than the crystalline one does. When heated with a laser to about degrees Celsius, the alloy switches from the original crystalline phase to the amorphous state, which then appears as a dark spot when the disc is played back.

These spots can be erased using the same laser at a lower power to heat the material to a temperature of degrees C or so; this process returns the alloy to its crystalline state.