https://www.sciencedaily.com/releases/2018/11/181109101409.htm

Compact discs might be falling out of fashion, but they may have inspired the next generation of computer nanotechnology. A glass layer in CDs consists of a phase-change material that can be encoded with information when light pulses cause crystals in small regions of the layer to either grow or melt.

Phase-change materials triggered by electrical impulses -- rather than light -- would offer new memory technologies with more stable and faster operation than that possible in many current types of memory devices. In addition, downscaling memory sites in phase-change materials could increase memory density. But this remains challenging because of the difficulty of controlling the crystal growth -- crystallization -- and melting -- amorphization -- processes.