Material Absorption

Light intensity decreases as it passes through a material, generally due to its conversion to other energy forms.

Light absorbed by the materials (substrate) being bonded generates heat and the conductive properties of many materials that are suitable for use as substrates can provide a good indication of the expected bonding factors such as spectral performance, specific UV adhesives etc. Dark materials absorb more visible light than UV light, clear materials can absorb UV light quite significantly. Most plastics absorb strongly below 300nm.