Light "flash" for about 30 seconds, seen by 2 state employees who confirmed the sighting to each other

Myself (a corrections officer for 8 years and 34 years old) and another corrections officer (4 years in corrections and 24 years old) at a prison at this approximate location, were walking to post and saw a light in the sky to the east, it appeared to fade in and fade back out with its brightest time being about 20 seconds. We both said out loud, "what is that" and it faded out. There was no obvious or visible other aircraft in the area before or after. We thought it may be the suns reflection on a plane going into or out of RIC, which is in the direction we saw the light, but nothing was visible after, as if it disappeared. We nervously joked about reporting it to our work but have both chosen not to. Both of us have good eye sight, were not tired and had good daylight to see by. We had just left our regular pre-work briefing, so I'm very sure of time and date.