The thermal stabilities of LPBS and HPBS were assessed using thermal gravimetric analysis (TGA) and compared to the respective PDMS-OH precursor polymers (Figure ). HPDMS-OH revealed a major degradation event at 439 °C where the former is tentatively assigned to the loss of low molar mass fragments and the latter to the thermal degradation of the polymer backbone. Upon reacting with boric acid to form HPBS, the ons et in degradation only increases by a few degrees and the weight loss becomes more abrupt. The slight change in thermal stability fits well with the smaller amount of SiO-B observed in the FTIR results, indicative of the formation of fewer B(OSi)3 crosslinking sites. On the other hand, LPBS shows a much larger increase in thermal stability of ~140 °C compared to its precursor PDMS-OH. The significant increase in thermal stability is in agreement with the earlier FTIR experiments indicating a much higher crosslinking density in LPBS than HPBS.