In contrast, Material 3 was not modified by the 690 nm, 1.10 mW diode laser for any exposure time up to 20 seconds (Fig. ). We attributed this result to a glass transition temperature for the polymer in Material 3 (Tg > 100 ºC) that is higher than the polymer in Materials 1 and 2 (~40 ºC). Therefore, higher local temperatures were thought to be required to modify this material. Gratifyingly, the presence of the g-Fe2O3 particles in Material 4 enabled polymer modification with this low-power laser. The modifications were less uniform than those observed for Materials 1 and 2, with both spiked structures and pits from apparent ablation resulting from exposure to the laser light. Despite the limited control in the modification, this result confirmed that the addition of g-Fe2O3 particles can indeed facilitate the key laser modification of poly(S-r-DCPD) in Material 4.