There are several UL certified and labeled glass products suitable for use in a vision lite kit. All of these are both fire-rated and impact-safety rated for use in fire doors.
PROTECT3 SAFETY GLASS – 20, 45, 60 and 90 minutes
SCHOTT PYRAN PLATINUM – 20, 45, 60 and 90 minutes
LAM20 – 20 minutes
TEMP20 – 20 minutes