Abstract
We make three kinds of low density glassy waters, low-density amorphous ice (LDA), amorphous solid water (ASW) and hyperquenched glassy water (HGW), and examine the changes in their Raman spectra of OH-stretching vibrational regions by annealing at 1 bar. The irreversible change in Raman profile for LDA is observed above its calorimetric glass transition temperature (Tg) of ∼130 K below 144 K. The degree of the change in Raman spectra of LDA at the annealing temperature appears to be different from those for ASW and HGW. These results suggest a possibility that the modification in the hydrogen-bonded network of LDA during the annealing occurs above the calorimetric Tg.