In article , Use-Author-

The only time I've heard of this happening it turned out that a plate
fell of a wall hanging and bounced down the stairs, hitting the pane
and breaking it. If it's a small pane, it's unlikely to be a thermal
effect - consider the temperature differential, it's tiny. Where in
the door is the glazing panel? What is the door made of?


J.B.

Spontaneous disintegration of normal toughened glass is a well known and
accepted fact within the industry. Pilkington makes a special type of
toughened glass which "reduces the risk" (their words not mine) for
situations where the normal risk is unacceptable.

--
Ziggur
"S'ils te mordent, mords-les"