Microscopic Aspects of Stretched Exponential Relaxation (SER)

The Scher-Lax-Phillips (SLP) universal minimalist model quantitatively explains stretching fractions beta(Tg) for a wide variety of relaxation experiments (nearly 50 altogether) on electronic and molecular glasses and deeply supercooled liquids by assuming that quasi-particle excitations indexed by Breit-Wigner channels diffuse to traps (sinks). This model is effective here in discussing in detail three experiments: luminescence in isoelectronic Zn(Se,Te) alloys, fibrous relaxation in orthoterphenyl (OTP) and related glasses and melts up to 1.15Tg, and relaxation of binary chalcogen melts probed by spin-polarized neutrons (T as high as 1.5Tg). The model is also compared to several other recent theories.