Time-resolved laser spectroscopy for the in situ characterization of methacrylate monomer flow within spruce

Time-resolved diffuse optical spectroscopy (TRS) was investigated as a nondestructive method to characterize the post-impregnation distribution of methacrylate monomers within spruce (Picea abies). TRS was also used to monitor the flow of methacrylate monomers in situ, within spruce, during impregnation with both spatial and temporal resolution. The data were compared to fluid flow models developed by Darcy and Bramhall demonstrating that neither of these models were able to accurately describe the experimental results, highlighting the need for development of new models. Nondestructive characterization by TRS did not require staining of the monomer treatment solution, multivariate analysis or complex sample pre-treatment, thus highlighting the facile applicability of this technique.