Pyrex Profile: Refrigerator Dishes (1947) 

Refrigerator dishes first appeared in late 1947 with the Multi-Colour set in red, blue and yellow.  More solid colours were added with Pink & Turquoise and the first printed patterns offered in these sizes were Butterprint and pink Gooseberry.
     
In most standard patterns, refrigerator dishes were sold in four-piece sets, usually called a "4-piece Oven, Refrigerator & Freezer Set", comprising two 501s (1½ cup), one 502 (1½ pt), one 503 (1½ Qt), and a lid for each.  Model numbers on some examples have a leading zero, e.g.: 0502, which is not significant.

    

Pyrex refrigerator dishes, Butterprint, solid Pink, images from 1960 catalogue
Butterprint and solid Pink refrigerator sets.  Images from 1960 catalogue.
Pyrex Refrigerator Dish set, image from 1956 advertisement      
Although it was emphasized that the dishes were suitable for absolutely any purpose, the 502 was ideally designed to hold one pound of butter and to be held easily in an average woman's hand.

(Photo: Multi-Colour refrigerator set.  Image from 1956 advertisement.)
        
Refrigerator dish lids changed during the late 1950s.  The older type is smooth down the centre of the top, with ribbing on either side.  Newer lids are fluted all across the underside and smooth on top.

    

Pyrex 501 refrigerator dish lids, two types
501 lids: newer type (left), older type (right).
  
Clear 501 & 502 refrigerator dishes could be purchased singly for about two years beginning around 1949.  All three sizes became available in clear Pyrex in the early 1980s.  Plain white Opal refrigerator dishes probably date to the mid 1950s, contemporary with Opal 400-series bowl sets.
   
Decorated refrigerator sets in opal Pyrex disappeared about 1981, and ordinary clear Pyrex and Fireside sets took their place during the early to mid 1980s.  Autumn Harvest was the last pattern to include refrigerator dishes, but they had already disappeared from Butterfly Gold and Spring Blossom Green in 1979.
      
Non-Standard Colours

Black:  Matte black 503 refrigerator dishes do not belong to any standard refrigerator set.  This colour & size was produced specifically for a third party company who paired it with a brass lid and candle-warmer, either as a single, or with two 503s in a dual candle-warmer.  Called a "Brass 'N' Black Casserole", these sets were marketed under the brand name "Starline by Rodney Kent".  Known advertising dates them to around 1956.
  
Red:  Solid red 502 & 503 refrigerator dishes were produced in the context of an insulated cooler set that might not be a regular production item.  It combines two 502s and one 503 with a styrofoam carrying case.  The three-part carrier stacks the dishes in two separate layers and a blue & white cord with red handles holds the unit together.  The styrofoam carrier is marked "CGW-S-C" on the bottom.
  
 
Source:

Imagining Consumers: Design and Innovation from Wedgwood to Corning, Regina Lee Blaszczyk.
      
    
Related Articles:  

Pyrex Profiles: Multi-Colour, Pink & TurquoiseButterprint, Gooseberry 
Clear Pyrex Profiles: Refrigerator Dishes, Fireside 
Two types of Spring Blossom Green refrigerator dishes?
Pyrex Model Numbers 
Opal Pyrex Advertising & Brochures 
Isn't that date incorrect?
Didn't you just copy this from a book?

More: Refrigerator Dishes