Critical absorbed dose of resinous adhesive material towards non-destructive chemical-state analysis using soft X-rays

Abstract The local electronic state of the N,N,N',N' -tetraglycidyl-4,4′-diaminodiphenylmethane epoxy resin cured with 4,4′-diaminodiphenylsulfone (TGDDM-DDS), one of model adhesive materials, was investigated by the O K-edge X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). The total-electron-yield XAS spectra for TGDDM-DDS as a function of the X-ray dose exhibit the exponential-like decrease in the curing-derived pre-edge intensity due to the radiation damage. The quantitative analysis on the pre-edge intensity with respect to the X-ray dose enables the determination of the critical absorbed dose for the chemical change on TGDDM-DDS as 3.83 ± 0.01 MGy at 300 K. By using resonant XES with the well-focused X-ray beam, we found that (i) the charged-particle equilibrium exists for the soft X-rays in the range of at least 0.001–0.847 mm 2 beam spot and that (ii) the half of the critical absorbed dose can be regarded as the limit indicator for the non-destructive chemical-state characterization on resinous adhesive materials and interfaces using soft X-rays.