Depends on what you mean by "infrared," as well as what you mean be transparent." There's near-IR (NIR), which goes from about 800nm to 2500nm. Medium wavelength IR (MWIR), going from 3000 to 5000 nm, and Long wavelength IR (LWIR) going from 8000 to 14000 nm.
If by transparent, you mean transmissive, then fine, otherwise you'll need to clarify.
NIR is transmitted by almost all silica-based glasses as well as a vvariety of plastics and polycarbonates. In fact, typical PCs used in sunglasses are actually more transmissive in NIR than the visible.
MWIR can be transmitted by sapphire, diamond, silicon, germanium, zinc selenide, zinc sulfide, magnesium fluoride, and some others I can't remember
LWIR can be transmitted by germanium, silicon, zinc selenide and some plastics.