How permanent is heat gun treatment in restoring faded black

I've been seeing all these videos about using a heat gun to restore faded plastics, especially exterior black trim pieces. How exactly does this work? Is the plastic melting again on the surface? Is

How to Permanently Restore Black Plastic Trim (Reviewed and

No Fade Fresh Color Depositing Semi Permanent Hair Color

The Best Methods for Plastic Trim Restorer Using Best Products - Issuu

Jeep Black Plastic Restoration: 3 Best Methods

How To Vinyl Wrap A Car and Care for It

How to Remove Scratches From Plastic

How Long Does Permanent Hair Color Last?

SoftSheen-Carson Dark and Lovely Fade Resist Hair Color, 376 Red

🎉🎉🎉ETL Safety Certification -- ETL Certification of PRULDE heat gun is conforms to UL STD 499 for North America usage 🔥🔥🔥ULTRA STURDY➤Working Time

PRULDE Heat Gun, LCD Digital Display Heat Shrink Gun, 5 Air Flows/120°F-1200°F Variable Temps/6 Nozzles For Crafting, Vinyl Wrap, Shrink Wrap N2030

clips - What is the name / code for this plastic piece? - Motor Vehicle Maintenance & Repair Stack Exchange

Can you use a heat gun to cure powder coating?