Enhanced time-resolved Fourier transform infrared spectroscopic imaging for reversible dynamics

Time-resolved (TR) Fourier transform infrared (FTIR) spectroscopic imaging provides noninvasively spatial and spectral observations of molecular dynamic processes in heterogeneous environments. The technique, however, is limited by the readout time of the imaging focal plane array detector due to a tradeoff between the multichannel detection advantage and the achievable temporal resolution. We describe a generalized implementation of TR-FTIR spectroscopic imaging that, without affecting data quality, allows potential measurements of up to 2 orders of magnitude greater in time resolution than previously reported; that is, time resolutions of milliseconds to tenths of milliseconds are achievable for reversible dynamic processes. As an example, molecular rotations occurring in embedded liquid crystalline microdomains are monitored with a 2.5 ms time resolution allowing an accurate determination of events inherent in the reorientation and relaxation processes.