8. Polymers

The change of state of a material is thermodynamically well defined, if for characteristic values of the thermodynamic coordinates, it results in a discontinuity of the essential physical characteristics.

The solid state is generally the result of such a change. On a microscopic scale, it is characterized by the fact that the material's constituent elements occupy well-defined, time-invariant relative positions. This gives rise to the characteristic that qualifies these materials as solids: they do not deform spontaneously, unlike liquids.

During the "solidification" of [12] glasses, and polymer glasses in particular, the so-called glass transition is not a thermodynamically characterized phase change. Instead, there is a continuous transition from liquid (or rubber) to "solid",...