yes Planck time is closely related to the Planck length and the speed of light. In actual fact both the photon and space time itself will have a component based on frequency
I tend to think time is more logically than physical ... what truly becomes timeless matter from a time-bound origin transcends the physical realm, either becomes oblivious or eternal ... being and happiness is lawless. that's the tricky part.
To be realistic, logically Time is measurement of events, event are based on physical entities and do deal with masses and none masses as well, known and unknown , the all physical and metaphysical phenomenon in diversity of dimensions; moreover biologic-ally measurements are relative ........!
Time can come under physical entity rather than just a calculation when some "Time particle/ wave/ force will get under observation having influence on design, structure, symmetry, patterns, characteristics etc.
For NOW time is not more than a quantification tool for events & behavior with help of "W" family....when to, what to, how to, where to, whom to.........!!
There is this insistence on the part of Einstein that time is frame-specific, that is, in the last instance is private.
30 years later, he came up with the same idea again, not really believing in it but proposing to test it: that correlated quantum objects might exist - in an observer-specific fashion.
This is what the "relativistic Bell experiment" in preparation by Anton Zeilinger for 15 years will show if the outcome is the currently expected one. A very frightening prospect -- very religious (if one goes to the last logical instance): The religiosity of Bell in his paper "Quantum mechanics for cosmologists" of 1994 which he wrote for his friend, the Dalai Lama.