Measurement of the degree of polarisation of thermally modified Scots pine using a Stokes imaging polarimeter

This study measured the polarised light reflected from the surface of thermally modified Scots pine (Pinus sylvestris L.) wood using a Stokes imaging polarimeter. The data were analysed using the Mueller matrix method. The Scots pine boards were heat treated in an oven at temperatures of 160 oC, 200 oC and 220 oC, with a heat treatment time of 3 h at the maximum temperature. The results indicated that the chemical composition of the thermally modified wood underwent a permanent transformation, leading to a change in the degree of polarisation of the reflected light. The presented method provides useful information for inspecting the quality of thermally modified wood products.