yes they do but thats why the unit that the de hqi comes with usually has a uv protective piece of glass blocking the uv rays. The single end hqi have this uv protective glass around the outer part of the bulb. So long story short dont look at a halide in the first place but especially with the uv screen off
i am pretty sure its just tempered glass. there are a few glass stores around that can custom cut and temper the glass for you.