Fracture surface characteristics of Te 2 As 3 Se 5 (TAS) glass fibers aged in light and in dark have been investigated respectively for understanding physical aging effect on their fracture behavior. The properties including tensile strength (ı), surface flaw depth (Į), and mirror radii (r m) were measured by DY30 Adamel Lomarghy and SEM respectively. Shape factor extracted by fitting of ı vs Į confirms that fractures of fibers aged in dark for 4 months originate from their surface flaw, but it does not work for fibers aged in light for 4 months. However, mirror constants (=ır m 1/2) of fracture surface for the TAS glass fibers aged in dark are in a good agreement with those aged in light. One possible reason is that the photoinduced effect changes the structure of glass surface during the physical aging.