Electric Privacy Glass ( Smart #glass ), or switchableglass, also called smart windows or switchable windows in its application.

to windows or skylights, refers to glass or glazing that changes light transmission properties when voltage, light or heat is applied.Smart glass controls the amount of light (and thereby heat) transmission. 

When activated, the glass changes from transparent to translucent, blocking some or all wavelengths of light.Smart glass technologies include electrochromic, photochromic, thermochromic, suspended particle,micro-blind and liquid crystal devices.