thread334-339176: Viscoelastic material for damping high frequencies?

This is my first post here after a days-long search on the net for information on this issue. Material science is not my specialisation, so I am very much at the mercy of your goodwill. Thanks in advance.

From the above post the following point was made:

Quote (At higher frequencies materials behave more stiffly and elastically. So, you need to use a material with very low glass transition temperature (Tg))

Taking that as two separate statements, would someone be able to explain, in simple terms, what it is about the nature of 'materials' (and I assume that in context that means all polymers?) that gives them different mechanical properties such as enhanced stiffness at raising frequencies, for example, 100Hz and 10kHz. What exactly is the relationship between elasticity, stiffness, damping (Td) and frequency for a given material, is that relationship unique to polymers, and indeed all polymers?

Thanks.