We used a Horiba™ LabRam HRevolution Raman spectrometer equipped with a motorized stage for mapping the fluorescence signal excited with a 532-nm solid-state diode laser from SENB submitted to a four-point bending test. The laser is focused through a microscope equipped with a long-working distance x50 Mitutoyo™ objective down to a spot of about 1µm. The high fluorescence signal allows a typical recording time τ of the order of one millisecond or less to obtain an intense enough fluorescence spectrum at each point and determine peak position and stress. X-Y maps of the sample lateral surface were obtained in the SWIFT™ mode where the sample is scanned at constant speed in the X direction (perpendicular to the notch, see Figure left) under the laser, and signalprocessed through the CCD detector to record individual points every τ. Spatial resolution is determined by the product of the scanning speed and reading time τ in the X direction, and by step-bystep motion in the Y direction (along notch). Identical steps were chosen in both X and Y directions to avoid potential distortion in the image, and set to 5 and 2 µm for low-and high-resolution images, respectively. Low-resolution images covering a 1 × 2 mm 2 field of view and high-resolution images covering 300 x 750 µm 2 were acquired in about one minute each around the crack. One image with steps of 0.5 µm over a 400 × 150 µm 2 area was acquired in 40 minutes at the end of the test (corresponding to a long crack propagation but without macroscopic failure of the sample) for comparison with post mortem imaging by SEM. The stress was maintained at a set value at each step while maps were acquired. With the optical setting and characteristics of the laser-material interaction, the actual resolution is better than 2 µm.