Lasivaiheita

Lasivaiheita is a term used in materials science to refer to the glassy or amorphous phases that a material can exhibit. In this sense, lasivaiheita describes non-crystalline states characterized by a lack of long-range atomic order, while often retaining some short-range structural organization. The concept is relevant across different material families, including inorganic oxides, chalcogenides, polymers, and metallic alloys. In some contexts, lasivaiheita also encompasses multiple distinct amorphous states within a single material, a phenomenon related to polyamorphism.

Characteristics of lasivaiheita include isotropy in many properties, unusual mechanical behavior compared with crystalline counterparts, and the absence of a sharp melting point. Instead, glasses undergo a glass transition at a characteristic temperature (Tg) where their viscosity and molecular mobility change dramatically. Below Tg, the material behaves like a rigid solid; above Tg, it becomes more rubbery or viscous. Glassy states can age and slowly relax toward lower-energy configurations, a process influenced by temperature, pressure, and composition.

Formation and stability depend on rapid cooling of liquids, specific compositional ranges that frustrate crystallization, or pressure-induced amorphization. Common examples of lasivaiheita include silicate glasses (such as silica), borates, certain polymer glasses, and metallic glasses. Some materials exhibit multiple amorphous forms (high- and low-density amorphous states), illustrating polyamorphism within lasivaiheita.

Study of lasivaiheita relies on techniques such as differential scanning calorimetry (DSC), X-ray and neutron scattering, and spectroscopy to characterize Tg, devitrification, and structural motifs. The field informs applications in optics, packaging, coatings, and advanced structural materials, where amorphous phases offer unique combinations of transparency, isotropy, and processability.