26
K. Adrjanowicz
carried out on increased pressure have revealed that the physical and chemical properties of matter may drastically change when subjected to increased pressure. At
high pressure, it is possible to achieve organic and inorganic materials with interesting physicochemical properties, sometimes not attainable by any other experimental attempt performed at atmospheric pressure [19–26]. For example, except the
pressure-induced polymorphic transformation [27], one of the most thrilling theoretically predicted applications of hydrostatic pressure is spontaneous enantiomers
separation from the racemic crystal above certain pressure [28]. For that reason, highpressure studies are the source of unique information about different phenomena or
processes of fundamental importance in science and technology. On increased pressure, we can expect spectacular changes in the molecular packing and the character
of the intermolecular interactions. This has a critical effect on the dynamic and thermodynamic properties, as well as the physicochemical stability of glass-forming
materials. Thus, it has been suggested to be a very promising parameter that controls
the crystallization tendency of glass-forming liquids [29]. On the other hand, we all
know that crystallization is a very complex phenomenon influenced by many factors
at the same time. Control over all of them is difficult, if not impossible. Therefore,
introducing pressure as another thermodynamic variable to control brings up an
additional parameter that potentially makes an in-depth understanding of the principle aspects related to crystallization mechanism and its characteristics far more
challenging.
In the field of crystallization carried out under high-pressure conditions, a lot of
work has been already reported for inorganic materials [20, 27, 30–33]. Most of them
have been carried out to understand changes in the morphology, crystalline structure,
and the phase diagram rather than the crystallization kinetics. On the other hand, the
importance of such information is critical to control the properties of the newly
evolving phases, especially in industrial processing when most of the processes are
carried out under varying temperature and pressure conditions.
Study the effect of pressure on crystallization propensity or structural transformation of minerals or silica glasses has attracted considerable attention because
of its importance in material science and geophysics [34–36]. Compression has
been also used to induce crystallization of molecular liquids or polymers, especially reaching very high degrees of crystallinity [19], obtaining crystal morphology
of desired features [37] or accelerating the crystallization rate [38, 39]. However, the
exact effect of pressure on the crystallization of glass-forming materials is somewhat
unclear. For example, for the low-molecular-weight glass-forming liquid triphenyl
phosphite (TPP) it has been observed that compression inhibit crystallization [40].
Likewise, increased pressure was found to retard crystal growth of cordierite glass
and increase the nucleation time [41]. In contrast, some other reports demonstrate
that compression induces crystallization and facilitates its progress. Just to mention
that crystallization rate of amorphous Si at pressures up to few GPa can be enhanced
by a factor of 10 over that at atmospheric pressure [31, 42]. These contrasting examples point out that our knowledge about the effect of pressure on the crystallization
of glass-forming materials is still very incomplete. This can be related to the fact that
most of the high-pressure research devoted to crystallization is performed at randomly
K. Adrjanowicz
carried out on increased pressure have revealed that the physical and chemical properties of matter may drastically change when subjected to increased pressure. At
high pressure, it is possible to achieve organic and inorganic materials with interesting physicochemical properties, sometimes not attainable by any other experimental attempt performed at atmospheric pressure [19–26]. For example, except the
pressure-induced polymorphic transformation [27], one of the most thrilling theoretically predicted applications of hydrostatic pressure is spontaneous enantiomers
separation from the racemic crystal above certain pressure [28]. For that reason, highpressure studies are the source of unique information about different phenomena or
processes of fundamental importance in science and technology. On increased pressure, we can expect spectacular changes in the molecular packing and the character
of the intermolecular interactions. This has a critical effect on the dynamic and thermodynamic properties, as well as the physicochemical stability of glass-forming
materials. Thus, it has been suggested to be a very promising parameter that controls
the crystallization tendency of glass-forming liquids [29]. On the other hand, we all
know that crystallization is a very complex phenomenon influenced by many factors
at the same time. Control over all of them is difficult, if not impossible. Therefore,
introducing pressure as another thermodynamic variable to control brings up an
additional parameter that potentially makes an in-depth understanding of the principle aspects related to crystallization mechanism and its characteristics far more
challenging.
In the field of crystallization carried out under high-pressure conditions, a lot of
work has been already reported for inorganic materials [20, 27, 30–33]. Most of them
have been carried out to understand changes in the morphology, crystalline structure,
and the phase diagram rather than the crystallization kinetics. On the other hand, the
importance of such information is critical to control the properties of the newly
evolving phases, especially in industrial processing when most of the processes are
carried out under varying temperature and pressure conditions.
Study the effect of pressure on crystallization propensity or structural transformation of minerals or silica glasses has attracted considerable attention because
of its importance in material science and geophysics [34–36]. Compression has
been also used to induce crystallization of molecular liquids or polymers, especially reaching very high degrees of crystallinity [19], obtaining crystal morphology
of desired features [37] or accelerating the crystallization rate [38, 39]. However, the
exact effect of pressure on the crystallization of glass-forming materials is somewhat
unclear. For example, for the low-molecular-weight glass-forming liquid triphenyl
phosphite (TPP) it has been observed that compression inhibit crystallization [40].
Likewise, increased pressure was found to retard crystal growth of cordierite glass
and increase the nucleation time [41]. In contrast, some other reports demonstrate
that compression induces crystallization and facilitates its progress. Just to mention
that crystallization rate of amorphous Si at pressures up to few GPa can be enhanced
by a factor of 10 over that at atmospheric pressure [31, 42]. These contrasting examples point out that our knowledge about the effect of pressure on the crystallization
of glass-forming materials is still very incomplete. This can be related to the fact that
most of the high-pressure research devoted to crystallization is performed at randomly