Determined the point of intersection of tangents to two branches of the thermograph.
In the attached thermograph, the first weight loss should be due to the volatile solvent evaporation and second thermal stage might be due to the thermal decomposition. The onset temperature (IDT) is about 475 oC. This obtained by drawing two tangent lines on the thermograph at around 475 oC since the decomposition has occurred about this temperature.
At 65 C there was the elimination of certain volatile content. And at the temperature around 550 to 600 the sample undergoes some crystalline change. It is not a mean that the sample is decomposed.It is a removal of some other content may be. In this graph there is no huge decomposition found. Need to go more temperature further.