these may be much more effective than the stuff my company used to install but this sounds like what we use to call Low-E coatings (15 years sonce I was in that industry though)

the principle back then (and i suppose today still) was/is to reflect all non visible light, ideally from the outer surface of the glass, so that the glass itself heats up as little as possible. This is tricky though as the coatings tend to be fragile so they tended to be applied to the inner surfaces of double glazed units (IGUs) to protect them. I was not on the marketing side so I don't recall how effective they apparently were.