A material's dimensional stability at room temperature is contingent upon its Glass Transition Temperature (Tg), a critical thermodynamic property. Tg signifies the temperature at which an amorphous or semi-crystalline substance transforms from a rigid, glass-like state to a more pliable, rubbery state. In the context of room temperature, which typically hovers around 20-25 degrees Celsius (68-77 degrees Fahrenheit), a material is considered dimensionally stable if its Tg significantly surpasses this range.

When a material exhibits a Tg considerably higher than room temperature, it implies that the material retains its rigid, glassy characteristics even when exposed to standard room conditions. This resilience results in the material maintaining its original dimensions, shape, and structural integrity. As a result, dimensional changes, warping, and deformations caused by temperature fluctuations or mechanical stress are effectively minimized.

On the contrary, if a material's Tg closely approaches or falls beneath room temperature, the material could transition into its rubbery state within those temperature parameters. This transition may lead to noticeable shifts in dimensions and an increased flexibility that could jeopardize the material's overall stability and performance in various applications.

Hence, the crucial aspect of ensuring a material's dimensional stability at room temperature rests upon the distinction between its Tg and the room temperature range. For optimal dimensional stability, a material's Tg should be notably higher than the typical room temperature. This discrepancy guarantees that the material remains firmly in its glassy state under standard room conditions, preserving its structural integrity and preventing undesirable dimensional alterations.