[Fizzlemizz]

For this example, you're creating a new texture every update. Create it once when you create the frame and adjust that texture.

local SPHowFrame = CreateFrame("Frame", nil, UIParent)
SPHowFrame:SetSize(50, 50)
SPHowFrame:SetPoint("CENTER")
SPHowFrame.texture = SPHowFrame:CreateTexture()
SPHowFrame.texture:SetAllPoints()
SPHowFrame.texture:SetTexture("Interface/Buttons/WHITE8X8")
 
local seconds = 0.5
local total = 0
 
local r = 0
local rud = 0.2
 
SPHowFrame:SetScript("OnUpdate", function(self, elapsed)
    total = total + elapsed
    if total > seconds then
      local r = getRedColor()
      print (r)
      self.texture:SetColorTexture(r, 0, 0)
      total = 0
    end
end)
 
 
function getRedColor()
   r = r + rud
   if r > 1 then
      rud = rud * -1
      r=1
   end 
   if r < 0 then 
      rud = rud * -1
      r=0
   end 
   
   return r
end