Window material

taken from http://www.zetatalk.com/shelter/slideloc/material.htm

One impressive material that could be used for blast proof windows as part
of a thin-shell enclosure is
Synthetic Sapphire. It's a clear, crystalline material that is stronger and
more heat resistant than any other
material known to mankind. It can withstand tensile or compressive loads up
to 600,000 pounds per square
inch.
Another impressive material is a Superalloy that is categorized as MAR 300.
It is a special steel with
a tensile or compressive strength of 300,000 pounds per square inch. Such
materials, if employed as the
material of the shell structures and windows would transform our physical
world environment into one of
durability, longevity, efficiency, and preparedness.