Complex sentence: Intrinsic strength refers to strength of a glass containing no flaws either in the bulk or on the surface and is determined by the chemical composition and molecular structure of a glass over a range of spatial scales.
Split into simpler sentences: Intrinsic strength refers to strength of a glass containing no flaws either in the bulk or on the surface. The intrinsic strength is determined by the chemical composition and molecular structure of a glass over a range of spatial scales.