Linked from
The 73 pages that link to Thermal decomposition, each with the reason it gives.
PyrolysisNarrower topic: Pyrolysis is a specific form of decomposition driven by heat.
Smoke pointNarrower topic: Smoke appears as heat breaks down fat molecules into volatile products.
Mercury(II) oxideNarrower topic: Heating HgO separates it into elemental mercury and oxygen.
Silver oxideNarrower topic: Heat can decompose silver oxide into silver and oxygen.