The sentence in which I use it similar to the following:
From this, it is possible to define a diffusion-time-dependent dimension.
I am not sure if the double hyphenation is correct or not, but I cannot rephrase the sentence with other words, so, please, don't suggest particular changes.
Furthermore, "diffusion time" is often found in literature without a hyphen, so maybe "diffusion time-dependent" is the correct choice, but it seems a bit wrong to me...
Could you explain what are the general rules for cases like this?