Technology

Okay, so you're talking about the IR that most people would refer to as thermal, rather than the IR that's technically NIR, and is used in most image intensification. My mistake; as you say, these things get slippery because most of the time people aren't talking about specific wavelengths and frequencies.

Yes, IR-as-in-thermal is going to be stopped by most glass. IR-as-in-NIR-for-NODs is not. The IR lasers and weapon lights that show up very well with NODs are definitely not visible to the naked human eye, so they're outside of the visible light spectrum, and get generally labeled as IR, even if they're outside of the spectrum of IR that's used by most thermal optics. (It would be interesting to see if a Steiner DBAL could illuminate an area that had low IR for a FLIR camera.) And yes, for that, a red dot sight will work, because it will be set to very, very dim; too dim to be seen by the naked eye.