Glass is used as an insulator because it has atoms that have electrons that are closely connected with each other. And because of this property, it does not allow electrons to freely roam around and be shared by nearby atoms thus preventing the flow of electrical current in other materials.

Is glass a thermal insulator?

In addition to being a good electrical insulator, glass has many other useful properties. It is a good thermal insulator (most material are either both or neither), and it is resistant to many corrosive chemicals. Because of their lack of crystal structure, glasses are sometimes called amorphous materials.

Why is glass a good insulator?

Glass is actually an insulator. It doesn’t allow the flow of electrons easily from atom to atom, as seen in substances like copper, and other metals which are excellent conductors of both heat and electricity. Insulators have electrons that are held tightly which means they aren’t shared between other atoms.