An equation, describing
crystallization kinetics, of the form:
where

is the crystalline
volume fraction developed at time

and constant temperature,

and

are suitable parameters.

is temperature dependent. According to the original theory,

should be an integer from 1 to 4, the value of which should depend only on the type
of the statistical model; however, it has become customary to regard it as an adjustable
parameter that may be non-integral.
Source: