  At optical/ultraviolet energies, blazars display an underlying thermal
(unpolarized) contribution from the accretion disc, torus and line emitting
regions, diluting the polarized emission from the jet-component. Optical
polarimetry can be used to disentangle the thermal and non-thermal components,
and place constraints on the particle populations and acceleration mechanisms
responsible for the non-thermal emission. We present the results of a linear
optical spectropolarimetric observing campaign of 18 blazars (6 BLLs and 12
FSRQs) undertaken with the Southern African Large Telescope between 2016 and
2022. This was done to observe these systems during flaring states, as well as
long term monitoring of PKS1510-089, AP Lib and PKS 1034-293. The observations
traced the frequency dependence of the degree and angle of polarization, as
well as changes in the spectral line strengths. We investigated possible
correlations between the polarization and other observed characteristics for
the sources. While an indication of correlation was found between the frequency
dependence and the average level of polarization for some sources, a
correlation was not found for the population as a whole. These results
highlight that continuous observations and in-depth modelling of polarization
and its frequency dependence is required to obtain a more holistic view of TeV
blazars.
