Strain relaxation in glass by optical correlation and pressure jump relaxation

Strain relaxation functions have been obtained for boron trioxide glass in its transformation region by digital correlation of a scattered optical beam and by pressure jump relaxation measurements utilizing a recently developed acoustic densitometer. The results confirm that the light−scattering correlation data is a measurement of the isothermal constant stress compressibility function. These measurements, together with previous ultrasonic results, cover a temperature region for B2O3 in which the structural relaxation time changes by more than 13 orders of magnitude.