  In this study, we use our recently prepared graphene oxide (GO) with an
almost intact {\sigma}-framework of C-atoms (ai-GO) to probe the thermal
stability of the carbon framework for the first time. Ai-GO exhibits few
defects only by preventing CO2 formation during synthesis. Ai-GO was thermally
treated before chemical reduction and subsequently the resulting defect density
in graphene was determined by statistical Raman microscopy. Surprisingly, the
carbon framework of ai-GO is stable in thin films up to 100 {\deg}C.
Furthermore, we find evidence for an increasing quality of ai-GO upon annealing
at 50 {\deg}C before reduction. The carbon framework of GO prepared according
to the popular Hummers method (GO-c)appears to be less stable and decomposition
starts at 50 {\deg}C what is qualitatively indicated by CO2-trapping
experiments in {\mu}m-thin films. Information about the stability of GO is
important for storing, processing and applying GO in applications.
