Understanding the kinetics between the components of time-resolved spectra is a crucial step in the study of photo-activated processes. However, modeling the kinetics requires usually some a priori knowledge about the system. In our approach, we build a Markov State Model (MSM) from the spectral data, and obtain a Koopman transition matrix K(τ). With genPCCA, an invariant subspace projection, we project the process into its metastable components. The result of the application of gen-PCCA is a transition matrix Kc(τ), from which we can read the transition probability between the metastable components of the reaction. We discuss the application of this analysis method to the transient absorption spectrum of brominated Al-corrole.