|MLA Citation:||Bloomfield, Louis A. "Question 1519"|
How Everything Works 19 Oct 2017. 19 Oct 2017 <http://howeverythingworks.org/print1.php?QNum=1519>.
The stresses frozen into the tempered glass affect its polarizability and give it strange characteristics when exposed to the electromagnetic fields in light. This stressed glass tends to rotate polarizations of the light passing through it. As a result, you see odd reflections of the sky (skylight is polarized to some extent). Those polarization effects become immediately apparent when you wear polarizing sunglasses.