reduced viscosity

Synonym: viscosity number
of a polymer

of a polymer

The ratio of the relative viscosity increment to the mass concentration of the polymer, $c$ , i.e. $η i c$ , where $η i$ is the relative viscosity increment.

Notes:

The unit must be specified; $cm 3 g −1$ is recommended.
This quantity is neither a viscosity nor a pure number. The term is to be looked on as a traditional name. Any replacement by consistent terminology would produce unnecessary confusion in the polymer literature. Synonymous with viscosity number.

Source:

Purple Book, p. 63