On heating the recovered high-pressure phase ice VIII at ambient pressure, the transitions to high-density amorphous (hda) and low-density amorphous ices, to cubic ice Ic, and finally to hexagonal ice Ih were observed using real-time neutron diffraction. A new form of ice, "defective ice VI", was prepared for the fist time by pressurizing ice Ih to 30 kbar at liquid nitrogen temperature. Vibrational spectra of ices Ih, hda, VI, VI’, and VIII prepared by different thermobaric treatments were studied by inelastic neutron scattering. The translational band of the intermolecular part of ice VI’ vibrational spectrum was shown to be similar to that of hda ice, whereas its Librational band was similar to that of ice VI. We conclude that ices VI, VI’, and hda have essentially the same atomic correlations and force constants, though with the different degree of disorder in the case of ices VI’ and hda.