Most studies report a depression of the glass transition temperature in thin polymer films. To gain insight into this behavior,
we have simultaneously investigated the structure of materials and their thermal behavior by developing an ATR–FTIR–nano-differential
scanning calorimeter (nanoDSC) hybrid instrument consisting of a ZnSe ATR crystal upon which the sample and a DSC-on-a-chip
rests. FTIR spectra showed property changes with film thickness; nanoDSC did not. The relative absorbance of an IR peak at
797 cm−1 was found to correlate with aging time in thin films, suggesting that conformational structure of thin films is critical
to their thermal behavior.