Before revision: Physical and chemical changes in biological interfaces can be quantified by corresponding changes in the thermodynamic state of the interface. Based on Einsteins approach to thermodynamics, we show that fluorescence spectra of a dye embedded in a lipid membrane is a function of the state of the interface. We derive the coupling between the energy fluctuations of a fluorophore and its environment allowing the thermodynamic susceptibility, in particular, the specific heat of the interface to be estimated from the spectra of the embedded fluorophore. The estimate of the thermodynamic susceptibility is shown to hold not only for quasi-static near-equilibrium measurements, but also for dynamic state changes in lipid vesicles induced by broadband pressure impulses of the order of 1 MPa peak amplitude and 10 microsecond  pulse duration.
After revision: Solvation shell dynamics is a critical determinant of protein and enzyme functions. Here we investigate how the dynamics of the solvation shell changes for molecules embedded in lipid vesicles induced by broadband pressure impulses of the order of 1 MPa peak amplitude and 10 microsecond pulse duration.