Preheat oven to 425 degrees. Line a pie pan with unbaked piecrust, then line the pie crust with parchment paper or foil. Fill with pie weights, rice or beans and bake 20 minutes Lift out paper or foil, prick bottom with sides of crust with a fork and bake 5-10 minutes longer or until crust is golden brown. Cool crust on a rack for 3 min then brush bottom and sides with egg white while warm. Set aside.
In a 2 quart saucepan, mix together the sugar and cornstarch. Gradually stir in orange juice concentrate and water until smooth. A few lumps of cornstarch may remain but they will smooth out when the sauce is cooked. Over medium heat bring to a boil, stirring constantly. Boil for 1 minute. Remove from heat and let cool completely.
Place raspberries in a bowl and pour over cooled orange glaze over them. Using a rubber spatula, fold raspberries into glaze, working gently to keep them from breaking up. Pour into crust and smooth top. Refrigerate for 4 hours or until set. Slice and serve with a dollop of whipped cream.