This article summarizes synchrotron wide-angle x-ray diffraction (WAXD) patterns, polarized attenuated Fourier transform infrared spectroscopy (ATR-FTIR) data and differential scanning calorimetry (DSC) data of differently stress-annealed poly(3-hydroxybutyrate) (P3HB) fibers. Additionally, in-situ polarized ATR-FTIR data has been measured under tensile drawing of pre-annealed P3HB fibers under low annealing stress. Modifications to the ATR-FTIR setup and sample holders for performing measurements on P3HB fibers are explained in the experimental section. For more information see 'Reversible mesophase in stress-annealed poly(3-hydroxybutyrate) fibers: A synchrotron x-ray and polarized ATR-FTIR study' [1] .