Micrographic observations of the carbonaceous mesophase by a quenching hot stage

A hot-stage microscope with quenching capability was employed to relate the observations made at the free surface of a pitch during pyrolysis to the bulk microstructure. Freshly formed mesophase spherules display an 'iceberg effect' with only a limited upper segment exposed to view. The mesophase layers tend to lie normal to the free surface, and + or - 2 Pi as well as + or - Pi disclinations display discontinuous cores at the free surface; aside from these minor effects, surface observations appear to be representative of events taking place within the bulk mesophase.