Glass Transition Temperature
Glass Transition Temperature - Related Videos
09:50
Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures
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Cited by 4 •
2017
A protocol for determining the vitreous phase densities of micro- to pico-liter size drops of aqueous mixtures at cryogenic temperatures is described.
02:31
Phase Transitions
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2020
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to occupy...
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The Looking Glass Self
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2025
The concept of the looking-glass self describes how an individual's self-concept is shaped by their perception of how others see them. This psychological theory, first introduced by sociologist Charles Horton Cooley in 1902, posits that self-identity emerges in a social context and is influenced by the judgments—real or imagined—of others.Research suggests that individuals frequently overestimate how positively others perceive them. This is particularly evident in physical self-perception,...
02:58
Properties of Transition Metals
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2020
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals. Figure 1: Periodic Table. The transition metals are located in groups 3–11 of the periodic table. The inner transition metals are in the two rows...
01:58
Cooperative Allosteric Transitions
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2020
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
FAQs
As temperature rises through the glass transition range, molecular motion and free volume increase. This added space allows molecules in the amorphous material to move more readily, changing rigidity and viscosity while enabling greater diffusion and permeability. In biological formulations, these shifts indicate that the matrix may no longer restrict molecular rearrangement as effectively.
Unlike crystallization, the glass transition does not create an ordered crystal structure. Instead, it reflects a change in the mobility of an already amorphous material as temperature changes. This distinction matters because a sample can soften, become less viscous, or permit faster diffusion and permeability while remaining noncrystalline, so stability predictions must consider molecular mobility as well as structure.
These functional properties respond to the combined effects of molecular motion and free volume. Greater mobility can reduce rigidity and viscosity while increasing the movement of molecules through the material, which affects diffusion and permeability. Evaluating these changes around the transition helps connect temperature conditions with the expected stability and performance of biological materials.
In biological preservation, glass transition temperature helps identify conditions that keep molecular mobility low. During drying, cooling, or storage, maintaining a less mobile state can slow chemical or structural damage. This principle supports stability planning for cells, proteins, vaccines, and tissues, where restricting molecular movement helps preserve biological structure and function.
The concept is relevant to sugars, polymers, membranes, and biomaterials, as well as preservation systems involving cells, proteins, vaccines, and tissues. These materials can show temperature-dependent changes in mobility and physical behavior. Examining their transition properties helps anticipate changes in rigidity, viscosity, diffusion, or permeability during handling, drying, cooling, and storage.
Researchers can compare the temperatures used during drying, cooling, or storage with the transition range identified for a material. Conditions that promote greater molecular mobility may signal increased risk of altered rigidity, diffusion, permeability, or chemical and structural damage. The transition therefore provides a stability reference for selecting and evaluating preservation conditions.