**2. Experimental**

X-ray non-crystalline *Zr*47.5*Cu*47.5*Al*5, *Zr*65*Cu*15*Al*10*Ni*10, *Zr*47*Cu*45*Al*7*Fe*1 and *Zr*52.5*Cu*17.9*Ni*14.6*Al*10*Ti*5 (at.%, labelled as *ZrAl*5, *ZrNi*10, *ZrFe*1 and *ZrTi*5 hereafter) produced as 5 × 2 × (40 − 50) mm<sup>3</sup> bars were used for the investigation. The choice of these glasses was conditioned by the following reasons. First, all above Zr-based glasses (either in the initial or preannealed states) display a level of the mechanical damping in the supercooled liquid state (i.e., above *Tg*), which is small enough to ensure automatic measurements of the shear modulus (see below). As noted earlier, a high enough damping level above *Tg* results in the loss of automatic resonant frequency tracking [21], which strongly limits the range of possible glass compositions. Second, these glasses have diverse and, in some sense, particular properties. Specifically, the *ZrNi*10 glass is very resistant to oxidation [22] that strongly favours precise calorimetric measurements on relatively small samples and their subsequent comparison with calculation results. The glasses *ZrAl*5 and *ZrFe*1 display, respectively, big and small compression plasticity [23] that could potentially affect their high temperature behavior. The *ZrTi*5 glass is being produced industrially for different applications and demonstrates enhanced corrosion resistance [24]. Besides that, the choice of the above MGs is conditioned by the fact that they can be fully crystallized (without any additional phase transformations) below the maximal temperature ( ≈900 K) achievable upon standard calorimetric measurements. Thus, it is important to check the IT approach sketched above on MGs displaying diverse physical properties.

Heat effects were measured by a Hitachi DSC 7020 instrument in flowing *N*2 (99.999%). The mass of the samples was 50–70 mg. Every DSC run on a glassy sample was taken up to the temperature of the full crystallization. It was next followed by the 2nd run on the same sample and the difference between the two runs was then calculated. It is this difference, which is shown below in Figure 2 and compared with Δ *W*-calculations performed using Equation (1).

The electromagnetic acoustic transformation (EMAT) method (see Ref. [25] for the method's details) was applied to measure the transverse resonant frequencies *f* (500–700 kHz) of 5 × 5 × 2 mm<sup>3</sup> samples at temperatures of up to 810 K in a vacuum of ≈0.01 Pa. For this purpose, frequency scanning was automatically performed every 10–15 s and the resonant frequency was determined as a maximal signal response received by the pick-up coil upon scanning. The half-width of the resonant curve was used to calculate the mechanical quality factor (equal to the inverse damping) and the latter was used to estimate the precision of resonant frequency determination. The shear modulus was then calculated as *G*(*T*) = *Grt f* <sup>2</sup>(*T*)/ *f* 2*rt*, where *frt* and *Grt* are the vibration frequency and shear modulus at room temperature, respectively. This way of *G*-calculation ignores possible density changes that can occur upon heating (usually less than 1%). The errors for the absolute *Grt*-values were accepted to be 1–2%. Then, the errors in the absolute *G*(*T*) data are about the same while the error in the measurements of *G*(*T*)-changes was estimated to be 5 ppm near room temperature and about 100 ppm near *Tg*. A heating/cooling rate of 3 K/min was accepted in all shear modulus and DSC measurements.

Three of the MGs under investigation (*ZrAl*5, *ZrNi*10 and *ZrFe*1) were tested in the initial state. This was impossible for the fourth glass (*ZrTi*5) because of the large damping near *Tg*, which results in the loss of EMAT automatic signal tracking. To avoid this effect, this MG was first annealed by heating into the supercooled liquid region and cooling back to room temperature. This MG is labelled as "relaxed" below. Both initial and relaxed MGs were first tested from room temperature up to temperatures of 780–810 K, which in all cases lead to the full crystallization. The second run for each glass was performed on the same sample in order to measure shear modulus *μ*(*T*) in the crystalline state.
