“The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. An amorphous solid that exhibits a glass transition is called a glass.”
The Nature article is clearer. https://www.nature.com/articles/s41598-025-88894-5: “Glass forms when a liquid is fast cooled preventing crystallization, across a reversible process known as the glass transition.
[…]
Here we demonstrate that material with glassy appearance found within the skull of a seemingly male human body entombed within the hot pyroclastic flow deposits of the 79 CE Vesuvius eruption formed by a unique process of vitrification of his brain at very high temperature”
The layman’s term includes such things as safety glass, which may have polymer layers.
So, confusingly, not all glass is “a glass”, and not all glasses are glass.
“The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. An amorphous solid that exhibits a glass transition is called a glass.”
The Nature article is clearer. https://www.nature.com/articles/s41598-025-88894-5: “Glass forms when a liquid is fast cooled preventing crystallization, across a reversible process known as the glass transition.
[…]
Here we demonstrate that material with glassy appearance found within the skull of a seemingly male human body entombed within the hot pyroclastic flow deposits of the 79 CE Vesuvius eruption formed by a unique process of vitrification of his brain at very high temperature”
The layman’s term includes such things as safety glass, which may have polymer layers.
So, confusingly, not all glass is “a glass”, and not all glasses are glass.