"Smart glass" is just a marketing term for a glass or plastic film with some chemical applied to it that can be made to either pass light / be transparent under certain conditions or become opaque or reflective.
These smart glasses can be categorized into Passive and Active types. Passive cannot be controlled manually as they do not react to electrial stimuli but to other things such as heat or lighting.
Active "smart glasses" change their state from mostly transparent to mostly opaque or reflective by electrical stimulation.
Active ones themselves can be divided further into 3 types: Electrochromic, Suspended Particle Device Technology (SPD) and Polymer Dispersed Liquid Crystal Switchable Technology (PDLC).
You can google how each works, but the general idea is electrochromic is slow especially for bigger sizes such as used for large windows.
I want to find out how fast the SPD or PDLC types can switch between on to off and off to on (on meaning opaque or reflective and off meaning transparent).
If they can be made to switch at 0.008 seconds they could act as a nice fast noiseless optical shutter for various applications that could switch their state at 120 Hz rate.
The only place I found about the switching state was a website selling commercial films to be applied on office windows and the site mentioned 0.05 seconds which is far from the 0.008, however do note it is not a scientific paper but a website and the speed beyond that shouldn't matter for the use case and could also be a limitation caused by the control board, not the physics of the materials involved.
I couldn't find any scientific paper on this. Is there any info how fast SPD and PDLC smart glasses or films can be made to switch their states? Right now I'm not even sure if the size of the glass or film matters. For most shutters it would be 1/10th or 1/100th of an office window size, so if size matters it could make a huge difference for other applications such as shutters/light blockers or reflectors in optical systems.
https://www.youtube.com/watch?v=SaZWW5nASZk&t=5s
LCD shutters use polarizers which reduces the transmitted light/ brightness to about 50% (of unpolarized light). Most smart glasses on the other hand are above 80% range.