transient phase (induction period)

https://doi.org/10.1351/goldbook.T06450
This expression relates to the period of time that elapses prior to the establishment of a @[email protected] Initially the concentration of a reactive intermediate is zero, and it rises to the steady-state concentration during the transient phase.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 189 [Terms] [Paper]