Is Glass 'liquid'?

Why I am asking this?? Well it’s not my fault, actually scientist are debating on this issue for decades. Some schools say that it is ‘solid’, while there is another significant large group, which says that it is ‘liquid’!

As far as it is concerned with ‘solid’ theory, we all can say that glass is solid, because it appears to be solid at room temperature. Let’s focus on the arguments and facts, what is said in favor of liquid theory. They say glass is never ‘solid’; rather it is ‘undercooled’ liquid! In solids such as iron, steel, and aluminum, the atoms are arranged very orderly, in a repeating pattern, like tiles on a bathroom wall. Because of the random atomic structure of glass, physicists tent to think of glass as a liquid which is supercooled. Metals and other materials, say ice are solid up to their melting point, where they suddenly turn into liquid. But glass is different. When you heat glass, there is never a sudden transition from solid to liquid. Rather, glass becomes gradually more deformable.

But if glass tends to have properties of ‘liquid’, then at least it should evince some of them?? Well, they claim, they can be seen, but we need to change the circumstances a bit to visualize the liquid properties of glass. Say, if glass is really liquid, then it should ‘flow’ like a liquid? The answer is, it really DOES flow! For example, if a window glass is kept vertical for a long time say for years, and we have sensitive measuring instruments, then we can really measure that the thickness of glass at the bottom is more than the top.

Some schools, who don’t believe in this theory, say that though glass molecules are not arranged in perfect order, but they can precipitate into crystals anytime if given a favorable condition say low temperature and pressure. It also depends on the facts that how rapidly a glass is cooled after it is heated. If a glass is cooled very slowly, then it will tend to form a crystal, and not a supercooled solid. They give many other arguments in support of its solid property with order of transition, viscosity and poises.

Whatever, but it is for sure, that none of the theories are 100% evident. So there is a fare good chance, that glass is actually a ‘liquid’!