Polymerisation-related changes in THz transmission in SU8 and polystyrene

THz TDS was used to study the effects of polymerisation on THz transmission in SU8 and polystyrene. SU8 samples, spun onto a THz-transparent polyethelene substrate, were cross-linked to varying degrees using different UV exposure times. Variations in THz absorption and refractive index were observed as a function of the exposure times. Polystyrene samples were prepared as monodispersed powders with varying molecular weights. Variations of the THz refractive index with molecular weight were observed and analysed using the Claussius-Mosotti equation for the dielectric constant.