To be precise, it is not frozen, but freezing.Since the glass retains the basic properties of the liquid, even in the conventional solid state.It is quite understandable objections - they say the glass is not flowing!Quite simply, at room temperature, it almost does not flow, rather flowing, but very slowly, but it's worth it just to heat, motion immediately becomes clear.
Heating glass or glassware to a temperature of 600 - 900 degrees completely changes its properties.Glass becomes soft and pliable, allowing you to give it any shape.
It is common to all amorphous substances, which include glass, and in this category you can include all the resins both natural and artificial, various adhesives, rubber, certain types of plastics.
course, there are differences in the temperatures
at which these materials lose their hardness, but the principle is the same everywhere.
main difference between amorphous to crystalline substances, that amorphous have ordered lattice.While maintaining close communications structure, amorphous material has no long-range order of atoms and molecules.Thus, typical for amorphous solids isotropy of the properties and the absence of a specific melting point.That is, as the temperature rises gradually softened amorphous body and quietly liquefy.
Hence, the crystalline body is different from the liquid, not only and not so much quantitative, but mainly qualitative.That is, an amorphous body can be safely regarded as an infinite liquid with viscosity.
As mankind acquainted with the glass and when to teach him to produce, it is already impossible to know.Obviously, it started with the introduction of natural analogues glass - obsidian and tektites.
We only know that the oldest one found to date products from man-made glass is considered to be light green bead size mm 9h5,5 discovered in the vicinity of the city of Thebes dating from 35 BC
Pliny is a legend and how there was a glass like soda vendors, moored to the bank, began to prepare dinner.Because they do not find a suitable stone, they had to prop boilers pieces of soda - and after some time soda warmed up and mixed with river sand.There was previously unknown liquid.Despite the fact that attempts to repeat the experiment proved unsuccessful, the tradition lives on.
Rather, the glass was obtained by people as a byproduct of copper smelting.