transition time

in electroanalytical chemistry
In chronopotentiometry and related techniques, the time that elapses between the instant at which current is applied and the instant at which the concentration of an electroactive substance B at the electrode-solution interface becomes indistinguishable from zero. In experimental practice the latter time is often taken to be the instant at which the rate of variation of the potential of the indicator electrode attains a maximum value.
Source:
PAC, 1985, 57, 1491 (Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)) on page 1504