Improved methods of detecting thermal exposure are provided herein. The provided methods utilize initially dormant luminescent probes incorporated into a matrix to form a composite. When exposed to heat over a period of time, the luminescent probes are “activated” through a molecular transformation initiated by thermal energy. The activated probes exhibit a luminescent profile based on the extent of thermal exposure, thereby providing an indicator of the thermal exposure experienced by the matrix. When the composite is used to produce a structural component of a vehicle (e.g., an aircraft), the methods provide a convenient, large-area indicator of thermal damage experienced by the structural component.